diff --git a/.claude/skills/docs-writer-blog/SKILL.md b/.claude/skills/docs-writer-blog/SKILL.md new file mode 100644 index 000000000..baa21c34d --- /dev/null +++ b/.claude/skills/docs-writer-blog/SKILL.md @@ -0,0 +1,756 @@ +--- +name: docs-writer-blog +description: Use when writing or editing files in src/content/blog/. Provides blog post structure and conventions. +--- + +# Blog Post Writer + +## Persona + +**Voice:** Official React team voice +**Tone:** Accurate, professional, forward-looking + +## Voice & Style + +For tone, capitalization, jargon, and prose patterns, invoke `/docs-voice`. + +--- + +## Frontmatter Schema + +All blog posts use this YAML frontmatter structure: + +```yaml +--- +title: "Title in Quotes" +author: Author Name(s) +date: YYYY/MM/DD +description: One or two sentence summary. +--- +``` + +### Field Details + +| Field | Format | Example | +|-------|--------|---------| +| `title` | Quoted string | `"React v19"`, `"React Conf 2024 Recap"` | +| `author` | Unquoted, comma + "and" for multiple | `The React Team`, `Dan Abramov and Lauren Tan` | +| `date` | `YYYY/MM/DD` with forward slashes | `2024/12/05` | +| `description` | 1-2 sentences, often mirrors intro | Summarizes announcement or content | + +### Title Patterns by Post Type + +| Type | Pattern | Example | +|------|---------|---------| +| Release | `"React vX.Y"` or `"React X.Y"` | `"React v19"` | +| Upgrade | `"React [VERSION] Upgrade Guide"` | `"How to Upgrade to React 18"` | +| Labs | `"React Labs: [Topic] – [Month Year]"` | `"React Labs: What We've Been Working On – February 2024"` | +| Conf | `"React Conf [YEAR] Recap"` | `"React Conf 2024 Recap"` | +| Feature | `"Introducing [Feature]"` or descriptive | `"Introducing react.dev"` | +| Security | `"[Severity] Security Vulnerability in [Component]"` | `"Critical Security Vulnerability in React Server Components"` | + +--- + +## Author Byline + +Immediately after frontmatter, add a byline: + +```markdown +--- + +Month DD, YYYY by [Author Name](social-link) + +--- +``` + +### Conventions + +- Full date spelled out: `December 05, 2024` +- Team posts link to `/community/team`: `[The React Team](/community/team)` +- Individual authors link to Twitter/X or Bluesky +- Multiple authors: Oxford comma before "and" +- Followed by horizontal rule `---` + +**Examples:** + +```markdown +December 05, 2024 by [The React Team](/community/team) + +--- +``` + +```markdown +May 3, 2023 by [Dan Abramov](https://bsky.app/profile/danabra.mov), [Sophie Alpert](https://twitter.com/sophiebits), and [Andrew Clark](https://twitter.com/acdlite) + +--- +``` + +--- + +## Universal Post Structure + +All blog posts follow this structure: + +1. **Frontmatter** (YAML) +2. **Author byline** with date +3. **Horizontal rule** (`---`) +4. **`` component** (1-3 sentences) +5. **Horizontal rule** (`---`) (optional) +6. **Main content sections** (H2 with IDs) +7. **Closing section** (Changelog, Thanks, etc.) + +--- + +## Post Type Templates + +### Major Release Announcement + +```markdown +--- +title: "React vX.Y" +author: The React Team +date: YYYY/MM/DD +description: React X.Y is now available on npm! In this post, we'll give an overview of the new features. +--- + +Month DD, YYYY by [The React Team](/community/team) + +--- + + + +React vX.Y is now available on npm! + + + +In our [Upgrade Guide](/blog/YYYY/MM/DD/react-xy-upgrade-guide), we shared step-by-step instructions for upgrading. In this post, we'll give an overview of what's new. + +- [What's new in React X.Y](#whats-new) +- [Improvements](#improvements) +- [How to upgrade](#how-to-upgrade) + +--- + +## What's new in React X.Y {/*whats-new*/} + +### Feature Name {/*feature-name*/} + +[Problem this solves. Before/after code examples.] + +For more information, see the docs for [`Feature`](/reference/react/Feature). + +--- + +## Improvements in React X.Y {/*improvements*/} + +### Improvement Name {/*improvement-name*/} + +[Description of improvement.] + +--- + +## How to upgrade {/*how-to-upgrade*/} + +See [How to Upgrade to React X.Y](/blog/YYYY/MM/DD/react-xy-upgrade-guide) for step-by-step instructions. + +--- + +## Changelog {/*changelog*/} + +### React {/*react*/} + +* Add `useNewHook` for [purpose]. ([#12345](https://github.com/react/react/pull/12345) by [@contributor](https://github.com/contributor)) + +--- + +_Thanks to [Name](url) for reviewing this post._ +``` + +### Upgrade Guide + +```markdown +--- +title: "React [VERSION] Upgrade Guide" +author: Author Name +date: YYYY/MM/DD +description: Step-by-step instructions for upgrading to React [VERSION]. +--- + +Month DD, YYYY by [Author Name](social-url) + +--- + + + +[Summary of upgrade and what this guide covers.] + + + + + +#### Stepping stone version {/*stepping-stone*/} + +[If applicable, describe intermediate upgrade steps.] + + + +In this post, we will guide you through the steps for upgrading: + +- [Installing](#installing) +- [Codemods](#codemods) +- [Breaking changes](#breaking-changes) +- [New deprecations](#new-deprecations) + +--- + +## Installing {/*installing*/} + +```bash +npm install --save-exact react@^X.Y.Z react-dom@^X.Y.Z +``` + +## Codemods {/*codemods*/} + + + +#### Run all React [VERSION] codemods {/*run-all-codemods*/} + +```bash +npx codemod@latest react/[VERSION]/migration-recipe +``` + + + +## Breaking changes {/*breaking-changes*/} + +### Removed: `apiName` {/*removed-api-name*/} + +`apiName` was deprecated in [Month YYYY (vX.X.X)](link). + +```js +// Before +[old code] + +// After +[new code] +``` + + + +Codemod [description]: + +```bash +npx codemod@latest react/[VERSION]/codemod-name +``` + + + +## New deprecations {/*new-deprecations*/} + +### Deprecated: `apiName` {/*deprecated-api-name*/} + +[Explanation and migration path.] + +--- + +Thanks to [Contributor](link) for reviewing this post. +``` + +### React Labs Research Update + +```markdown +--- +title: "React Labs: What We've Been Working On – [Month Year]" +author: Author1, Author2, and Author3 +date: YYYY/MM/DD +description: In React Labs posts, we write about projects in active research and development. +--- + +Month DD, YYYY by [Author1](url), [Author2](url), and [Author3](url) + +--- + + + +In React Labs posts, we write about projects in active research and development. We've made significant progress since our [last update](/blog/previous-labs-post), and we'd like to share our progress. + + + +[Optional: Roadmap disclaimer about timelines] + +--- + +## Feature Name {/*feature-name*/} + + + +`` is now available in React's Canary channel. + + + +[Description of feature, motivation, current status.] + +### Subsection {/*subsection*/} + +[Details, examples, use cases.] + +--- + +## Research Area {/*research-area*/} + +[Problem space description. Status communication.] + +This research is still early. We'll share more when we're further along. + +--- + +_Thanks to [Reviewer](url) for reviewing this post._ + +Thanks for reading, and see you in the next update! +``` + +### React Conf Recap + +```markdown +--- +title: "React Conf [YEAR] Recap" +author: Author1 and Author2 +date: YYYY/MM/DD +description: Last week we hosted React Conf [YEAR]. In this post, we'll summarize the talks and announcements. +--- + +Month DD, YYYY by [Author1](url) and [Author2](url) + +--- + + + +Last week we hosted React Conf [YEAR] [where we announced [key announcements]]. + + + +--- + +The entire [day 1](youtube-url) and [day 2](youtube-url) streams are available online. + +## Day 1 {/*day-1*/} + +_[Watch the full day 1 stream here.](youtube-url)_ + +[Description of day 1 opening and keynote highlights.] + +Watch the full day 1 keynote here: + + + +## Day 2 {/*day-2*/} + +_[Watch the full day 2 stream here.](youtube-url)_ + +[Day 2 summary.] + + + +## Q&A {/*q-and-a*/} + +* [Q&A Title](youtube-url) hosted by [Host](url) + +## And more... {/*and-more*/} + +We also heard talks including: +* [Talk Title](youtube-url) by [Speaker](url) + +## Thank you {/*thank-you*/} + +Thank you to all the staff, speakers, and participants who made React Conf [YEAR] possible. + +See you next time! +``` + +### Feature/Tool Announcement + +```markdown +--- +title: "Introducing [Feature Name]" +author: Author Name +date: YYYY/MM/DD +description: Today we are announcing [feature]. In this post, we'll explain [what this post covers]. +--- + +Month DD, YYYY by [Author Name](url) + +--- + + + +Today we are [excited/thrilled] to announce [feature]. [What this means for users.] + + + +--- + +## tl;dr {/*tldr*/} + +* Key announcement point with [relevant link](/path). +* What users can do now. +* Availability or adoption information. + +## What is [Feature]? {/*what-is-feature*/} + +[Explanation of the feature/tool.] + +## Why we built this {/*why-we-built-this*/} + +[Motivation, history, problem being solved.] + +## Getting started {/*getting-started*/} + +To install [feature]: + + +npm install package-name + + +[You can find more documentation here.](/path/to/docs) + +## What's next {/*whats-next*/} + +[Future plans and next steps.] + +## Thank you {/*thank-you*/} + +[Acknowledgments to contributors.] + +--- + +Thanks to [Reviewer](url) for reviewing this post. +``` + +### Security Announcement + +```markdown +--- +title: "[Severity] Security Vulnerability in [Component]" +author: The React Team +date: YYYY/MM/DD +description: Brief summary of the vulnerability. A fix has been published. We recommend upgrading immediately. + +--- + +Month DD, YYYY by [The React Team](/community/team) + +--- + + + +[One or two sentences summarizing the vulnerability.] + +We recommend upgrading immediately. + + + +--- + +On [date], [researcher] reported a security vulnerability that allows [description]. + +This vulnerability was disclosed as [CVE-YYYY-NNNNN](https://www.cve.org/CVERecord?id=CVE-YYYY-NNNNN) and is rated CVSS [score]. + +The vulnerability is present in versions [list] of: + +* [package-name](https://www.npmjs.com/package/package-name) + +## Immediate Action Required {/*immediate-action-required*/} + +A fix was introduced in versions [linked versions]. Upgrade immediately. + +### Affected frameworks {/*affected-frameworks*/} + +[List of affected frameworks with npm links.] + +### Vulnerability overview {/*vulnerability-overview*/} + +[Technical explanation of the vulnerability.] + +## Update Instructions {/*update-instructions*/} + +### Framework Name {/*update-framework-name*/} + +```bash +npm install package@version +``` + +## Timeline {/*timeline*/} + +* **November 29th**: [Researcher] reported the vulnerability. +* **December 1st**: Fix was created and validated. +* **December 3rd**: Fix published and CVE disclosed. + +## Attribution {/*attribution*/} + +Thank you to [Researcher Name](url) for discovering and reporting this vulnerability. +``` + +--- + +## Heading Conventions + +### ID Syntax + +All headings require IDs using CSS comment syntax: + +```markdown +## Heading Text {/*heading-id*/} +``` + +### ID Rules + +- Lowercase +- Kebab-case (hyphens for spaces) +- Remove special characters (apostrophes, colons, backticks) +- Concise but descriptive + +### Heading Patterns + +| Context | Example | +|---------|---------| +| Feature section | `## New Feature: Automatic Batching {/*new-feature-automatic-batching*/}` | +| New hook | `### New hook: \`useActionState\` {/*new-hook-useactionstate*/}` | +| API in backticks | `### \`\` {/*activity*/}` | +| Removed API | `#### Removed: \`propTypes\` {/*removed-proptypes*/}` | +| tl;dr section | `## tl;dr {/*tldr*/}` | + +--- + +## Component Usage Guide + +### Blog-Appropriate Components + +| Component | Usage in Blog | +|-----------|---------------| +| `` | **Required** - Opening summary after byline | +| `` | Callouts, caveats, important clarifications | +| `` | Warnings about common mistakes | +| `` | Optional technical deep dives (use sparingly) | +| `` | CLI/installation commands | +| `` | Console error/warning output | +| `` | Multi-line console output | +| `` | Conference video embeds | +| `` | Visual explanations | +| `` | Auto-generated table of contents | + +### `` Pattern + +Always wrap opening paragraph: + +```markdown + + +React 19 is now available on npm! + + +``` + +### `` Patterns + +**Simple note:** +```markdown + + +For React Native users, React 18 ships with the New Architecture. + + +``` + +**Titled note (H4 inside):** +```markdown + + +#### React 18.3 has also been published {/*react-18-3*/} + +To help with the upgrade, we've published `react@18.3`... + + +``` + +### `` Pattern + +```markdown + +npm install react@latest react-dom@latest + +``` + +### `` Pattern + +```markdown + +``` + +--- + +## Link Patterns + +### Internal Links + +| Type | Pattern | Example | +|------|---------|---------| +| Blog post | `/blog/YYYY/MM/DD/slug` | `/blog/2024/12/05/react-19` | +| API reference | `/reference/react/HookName` | `/reference/react/useState` | +| Learn section | `/learn/topic-name` | `/learn/react-compiler` | +| Community | `/community/team` | `/community/team` | + +### External Links + +| Type | Pattern | +|------|---------| +| GitHub PR | `[#12345](https://github.com/react/react/pull/12345)` | +| GitHub user | `[@username](https://github.com/username)` | +| Twitter/X | `[@username](https://x.com/username)` | +| Bluesky | `[Name](https://bsky.app/profile/handle)` | +| CVE | `[CVE-YYYY-NNNNN](https://www.cve.org/CVERecord?id=CVE-YYYY-NNNNN)` | +| npm package | `[package](https://www.npmjs.com/package/package)` | + +### "See docs" Pattern + +```markdown +For more information, see the docs for [`useActionState`](/reference/react/useActionState). +``` + +--- + +## Changelog Format + +### Bullet Pattern + +```markdown +* Add `useTransition` for concurrent rendering. ([#10426](https://github.com/react/react/pull/10426) by [@acdlite](https://github.com/acdlite)) +* Fix `useReducer` observing incorrect props. ([#22445](https://github.com/react/react/pull/22445) by [@josephsavona](https://github.com/josephsavona)) +``` + +**Structure:** `Verb` + backticked API + description + `([#PR](url) by [@user](url))` + +**Verbs:** Add, Fix, Remove, Make, Improve, Allow, Deprecate + +### Section Organization + +```markdown +## Changelog {/*changelog*/} + +### React {/*react*/} + +* [changes] + +### React DOM {/*react-dom*/} + +* [changes] +``` + +--- + +## Acknowledgments Format + +### Post-closing Thanks + +```markdown +--- + +Thanks to [Name](url), [Name](url), and [Name](url) for reviewing this post. +``` + +Or italicized: + +```markdown +_Thanks to [Name](url) for reviewing this post._ +``` + +### Update Notes + +For post-publication updates: + +```markdown + + +[Updated content] + +----- + +_Updated January 26, 2026._ + + +``` + +--- + +## Tone & Length by Post Type + +| Type | Tone | Length | Key Elements | +|------|------|--------|--------------| +| Release | Celebratory, informative | Medium-long | Feature overview, upgrade link, changelog | +| Upgrade | Instructional, precise | Long | Step-by-step, codemods, breaking changes | +| Labs | Transparent, exploratory | Medium | Status updates, roadmap disclaimers | +| Conf | Enthusiastic, community-focused | Medium | YouTube embeds, speaker credits | +| Feature | Excited, explanatory | Medium | tl;dr, "why", getting started | +| Security | Urgent, factual | Short-medium | Immediate action, timeline, CVE | + +--- + +## Do's and Don'ts + +**Do:** +- Focus on facts over marketing +- Say "upcoming" explicitly for unreleased features +- Include FAQ sections for major announcements +- Credit contributors and link to GitHub +- Use "we" voice for team posts +- Link to upgrade guides from release posts +- Include table of contents for long posts +- End with acknowledgments + +**Don't:** +- Promise features not yet available +- Rewrite history (add update notes instead) +- Break existing URLs +- Use hyperbolic language ("revolutionary", "game-changing") +- Skip the `` component +- Forget heading IDs +- Use heavy component nesting in blogs +- Make time estimates or predictions + +--- + +## Updating Old Posts + +- Never break existing URLs; add redirects when URLs change +- Don't rewrite history; add update notes instead: + ```markdown + + + [Updated information] + + ----- + + _Updated Month Year._ + + + ``` + +--- + +## Critical Rules + +1. **Heading IDs required:** `## Title {/*title-id*/}` +2. **`` required:** Every post starts with `` component +3. **Byline required:** Date + linked author(s) after frontmatter +4. **Date format:** Frontmatter uses `YYYY/MM/DD`, byline uses `Month DD, YYYY` +5. **Link to docs:** New APIs must link to reference documentation +6. **Security posts:** Always include "We recommend upgrading immediately" + +--- + +## Components Reference + +For complete MDX component patterns, invoke `/docs-components`. + +Blog posts commonly use: ``, ``, ``, ``, ``, ``, ``, ``. + +Prefer inline explanations over heavy component usage. diff --git a/.claude/skills/react-expert/SKILL.md b/.claude/skills/react-expert/SKILL.md new file mode 100644 index 000000000..c252f6ce0 --- /dev/null +++ b/.claude/skills/react-expert/SKILL.md @@ -0,0 +1,335 @@ +--- +name: react-expert +description: Use when researching React APIs or concepts for documentation. Use when you need authoritative usage examples, caveats, warnings, or errors for a React feature. +--- + +# React Expert Research Skill + +## Overview + +This skill produces exhaustive documentation research on any React API or concept by searching authoritative sources (tests, source code, PRs, issues) rather than relying on LLM training knowledge. + + +**Skepticism Mandate:** You must be skeptical of your own knowledge. Claude is often trained on outdated or incorrect React patterns. Treat source material as the sole authority. If findings contradict your prior understanding, explicitly flag this discrepancy. + +**Red Flags - STOP if you catch yourself thinking:** +- "I know this API does X" → Find source evidence first +- "Common pattern is Y" → Verify in test files +- Generating example code → Must have source file reference + + +## Invocation + +``` +/react-expert useTransition +/react-expert suspense boundaries +/react-expert startTransition +``` + +## Sources (Priority Order) + +1. **React Repo Tests** - Most authoritative for actual behavior +2. **React Source Code** - Warnings, errors, implementation details +3. **Git History** - Commit messages with context +4. **GitHub PRs & Comments** - Design rationale (via `gh` CLI) +5. **GitHub Issues** - Confusion/questions (react/react + reactjs/react.dev) +6. **React Working Group** - Design discussions for newer APIs +7. **Flow Types** - Source of truth for type signatures +8. **TypeScript Types** - Note discrepancies with Flow +9. **Current react.dev docs** - Baseline (not trusted as complete) + +**No web search** - No Stack Overflow, blog posts, or web searches. GitHub API via `gh` CLI is allowed. + +## Workflow + +### Step 1: Setup React Repo + +First, ensure the React repo is available locally: + +```bash +# Check if React repo exists, clone or update +if [ -d ".claude/react" ]; then + cd .claude/react && git pull origin main +else + git clone --depth=100 https://github.com/react/react.git .claude/react +fi +``` + +Get the current commit hash for the research document: +```bash +cd .claude/react && git rev-parse --short HEAD +``` + +### Step 2: Dispatch 6 Parallel Research Agents + +Spawn these agents IN PARALLEL using the Task tool. Each agent receives the skepticism preamble: + +> "You are researching React's ``. CRITICAL: Do NOT rely on your prior knowledge about this API. Your training may contain outdated or incorrect patterns. Only report what you find in the source files. If your findings contradict common understanding, explicitly highlight this discrepancy." + +| Agent | subagent_type | Focus | Instructions | +|-------|---------------|-------|--------------| +| test-explorer | Explore | Test files for usage patterns | Search `.claude/react/packages/*/src/__tests__/` for test files mentioning the topic. Extract actual usage examples WITH file paths and line numbers. | +| source-explorer | Explore | Warnings/errors in source | Search `.claude/react/packages/*/src/` for console.error, console.warn, and error messages mentioning the topic. Document trigger conditions. | +| git-historian | Explore | Commit messages | Run `git log --all --grep="" --oneline -50` in `.claude/react`. Read full commit messages for context. | +| pr-researcher | Explore | PRs introducing/modifying API | Run `gh pr list -R react/react --search "" --state all --limit 20`. Read key PR descriptions and comments. | +| issue-hunter | Explore | Issues showing confusion | Search issues in both `react/react` and `reactjs/react.dev` repos. Look for common questions and misunderstandings. | +| types-inspector | Explore | Flow + TypeScript signatures | Find Flow types in `.claude/react/packages/*/src/*.js` (look for `@flow` annotations). Find TS types in `.claude/react/packages/*/index.d.ts`. Note discrepancies. | + +### Step 3: Agent Prompts + +Use these exact prompts when spawning agents: + +#### test-explorer +``` +You are researching React's . + +CRITICAL: Do NOT rely on your prior knowledge about this API. Your training may contain outdated or incorrect patterns. Only report what you find in the source files. + +Your task: Find test files in .claude/react that demonstrate usage. + +1. Search for test files: Glob for `**/__tests__/**/**` and `**/__tests__/**/*.js` then grep for +2. For each relevant test file, extract: + - The test description (describe/it blocks) + - The actual usage code + - Any assertions about behavior + - Edge cases being tested +3. Report findings with exact file paths and line numbers + +Format your output as: +## Test File: +### Test: "" +```javascript + +``` +**Behavior:** +``` + +#### source-explorer +``` +You are researching React's . + +CRITICAL: Do NOT rely on your prior knowledge about this API. Only report what you find in the source files. + +Your task: Find warnings, errors, and implementation details for . + +1. Search .claude/react/packages/*/src/ for: + - console.error mentions of + - console.warn mentions of + - Error messages mentioning + - The main implementation file +2. For each warning/error, document: + - The exact message text + - The condition that triggers it + - The source file and line number + +Format your output as: +## Warnings & Errors +| Message | Trigger Condition | Source | +|---------|------------------|--------| +| "" | | | + +## Implementation Notes + +``` + +#### git-historian +``` +You are researching React's . + +CRITICAL: Do NOT rely on your prior knowledge. Only report what you find in git history. + +Your task: Find commit messages that explain design decisions. + +1. Run: cd .claude/react && git log --all --grep="" --oneline -50 +2. For significant commits, read full message: git show --stat +3. Look for: + - Initial introduction of the API + - Bug fixes (reveal edge cases) + - Behavior changes + - Deprecation notices + +Format your output as: +## Key Commits +### - +**Date:** +**Context:** +**Impact:** +``` + +#### pr-researcher +``` +You are researching React's . + +CRITICAL: Do NOT rely on your prior knowledge. Only report what you find in PRs. + +Your task: Find PRs that introduced or modified . + +1. Run: gh pr list -R react/react --search "" --state all --limit 20 --json number,title,url +2. For promising PRs, read details: gh pr view -R react/react +3. Look for: + - The original RFC/motivation + - Design discussions in comments + - Alternative approaches considered + - Breaking changes + +Format your output as: +## Key PRs +### PR #: +**URL:** <url> +**Summary:** <what it introduced/changed> +**Design Rationale:** <why this approach> +**Discussion Highlights:** <key points from comments> +``` + +#### issue-hunter +``` +You are researching React's <TOPIC>. + +CRITICAL: Do NOT rely on your prior knowledge. Only report what you find in issues. + +Your task: Find issues that reveal common confusion about <TOPIC>. + +1. Search react/react: gh issue list -R react/react --search "<topic>" --state all --limit 20 --json number,title,url +2. Search reactjs/react.dev: gh issue list -R reactjs/react.dev --search "<topic>" --state all --limit 20 --json number,title,url +3. For each issue, identify: + - What the user was confused about + - What the resolution was + - Any gotchas revealed + +Format your output as: +## Common Confusion +### Issue #<number>: <title> +**Repo:** <react/react or reactjs/react.dev> +**Confusion:** <what they misunderstood> +**Resolution:** <correct understanding> +**Gotcha:** <if applicable> +``` + +#### types-inspector +``` +You are researching React's <TOPIC>. + +CRITICAL: Do NOT rely on your prior knowledge. Only report what you find in type definitions. + +Your task: Find and compare Flow and TypeScript type signatures for <TOPIC>. + +1. Flow types (source of truth): Search .claude/react/packages/*/src/*.js for @flow annotations related to <topic> +2. TypeScript types: Search .claude/react/packages/*/index.d.ts and @types/react +3. Compare and note any discrepancies + +Format your output as: +## Flow Types (Source of Truth) +**File:** <path> +```flow +<exact type definition> +``` + +## TypeScript Types +**File:** <path> +```typescript +<exact type definition> +``` + +## Discrepancies +<any differences between Flow and TS definitions> +``` + +### Step 4: Synthesize Results + +After all agents complete, combine their findings into a single research document. + +**DO NOT add information from your own knowledge.** Only include what agents found in sources. + +### Step 5: Save Output + +Write the final document to `.claude/research/<topic>.md` + +Replace spaces in topic with hyphens (e.g., "suspense boundaries" → "suspense-boundaries.md") + +## Output Document Template + +```markdown +# React Research: <topic> + +> Generated by /react-expert on YYYY-MM-DD +> Sources: React repo (commit <hash>), N PRs, M issues + +## Summary + +[Brief summary based SOLELY on source findings, not prior knowledge] + +## API Signature + +### Flow Types (Source of Truth) + +[From types-inspector agent] + +### TypeScript Types + +[From types-inspector agent] + +### Discrepancies + +[Any differences between Flow and TS] + +## Usage Examples + +### From Tests + +[From test-explorer agent - with file:line references] + +### From PRs/Issues + +[Real-world patterns from discussions] + +## Caveats & Gotchas + +[Each with source link] + +- **<gotcha>** - Source: <link> + +## Warnings & Errors + +| Message | Trigger Condition | Source File | +|---------|------------------|-------------| +[From source-explorer agent] + +## Common Confusion + +[From issue-hunter agent] + +## Design Decisions + +[From git-historian and pr-researcher agents] + +## Source Links + +### Commits +- <hash>: <description> + +### Pull Requests +- PR #<number>: <title> - <url> + +### Issues +- Issue #<number>: <title> - <url> +``` + +## Common Mistakes to Avoid + +1. **Trusting prior knowledge** - If you "know" something about the API, find the source evidence anyway +2. **Generating example code** - Every code example must come from an actual source file +3. **Skipping agents** - All 6 agents must run; each provides unique perspective +4. **Summarizing without sources** - Every claim needs a file:line or PR/issue reference +5. **Using web search** - No Stack Overflow, no blog posts, no social media + +## Verification Checklist + +Before finalizing the research document: + +- [ ] React repo is at `.claude/react` with known commit hash +- [ ] All 6 agents were spawned in parallel +- [ ] Every code example has a source file reference +- [ ] Warnings/errors table has source locations +- [ ] No claims made without source evidence +- [ ] Discrepancies between Flow/TS types documented +- [ ] Source links section is complete diff --git a/.github/ISSUE_TEMPLATE/config.yml b/.github/ISSUE_TEMPLATE/config.yml index 63e310e0b..de2bfc362 100644 --- a/.github/ISSUE_TEMPLATE/config.yml +++ b/.github/ISSUE_TEMPLATE/config.yml @@ -1,6 +1,6 @@ contact_links: - name: 📃 Bugs in React - url: https://github.com/facebook/react/issues/new/choose + url: https://github.com/react/react/issues/new/choose about: This issue tracker is not for bugs in React. Please file React issues here. - name: 🤔 Questions and Help url: https://reactjs.org/community/support.html diff --git a/.github/workflows/discord_notify.yml b/.github/workflows/discord_notify.yml new file mode 100644 index 000000000..97f8d183b --- /dev/null +++ b/.github/workflows/discord_notify.yml @@ -0,0 +1,32 @@ +name: Discord Notify + +on: + pull_request_target: + types: [opened, ready_for_review] + +permissions: {} + +jobs: + check_maintainer: + uses: react/react/.github/workflows/shared_check_maintainer.yml@main + permissions: + # Used by check_maintainer + contents: read + with: + actor: ${{ github.event.pull_request.user.login }} + + notify: + if: ${{ needs.check_maintainer.outputs.is_core_team == 'true' }} + needs: check_maintainer + runs-on: ubuntu-latest + steps: + - name: Discord Webhook Action + uses: tsickert/discord-webhook@v6.0.0 + with: + webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }} + embed-author-name: ${{ github.event.pull_request.user.login }} + embed-author-url: ${{ github.event.pull_request.user.html_url }} + embed-author-icon-url: ${{ github.event.pull_request.user.avatar_url }} + embed-title: '#${{ github.event.number }} (+${{github.event.pull_request.additions}} -${{github.event.pull_request.deletions}}): ${{ github.event.pull_request.title }}' + embed-description: ${{ github.event.pull_request.body }} + embed-url: ${{ github.event.pull_request.html_url }} diff --git a/.github/workflows/label_core_team_prs.yml b/.github/workflows/label_core_team_prs.yml new file mode 100644 index 000000000..4cb6fbc71 --- /dev/null +++ b/.github/workflows/label_core_team_prs.yml @@ -0,0 +1,41 @@ +name: Label Core Team PRs + +on: + pull_request_target: + +permissions: {} + +env: + TZ: /usr/share/zoneinfo/America/Los_Angeles + # https://github.com/actions/cache/blob/main/tips-and-workarounds.md#cache-segment-restore-timeout + SEGMENT_DOWNLOAD_TIMEOUT_MINS: 1 + +jobs: + check_maintainer: + uses: react/react/.github/workflows/shared_check_maintainer.yml@main + permissions: + # Used by check_maintainer + contents: read + with: + actor: ${{ github.event.pull_request.user.login }} + + label: + if: ${{ needs.check_maintainer.outputs.is_core_team == 'true' }} + runs-on: ubuntu-latest + needs: check_maintainer + permissions: + # Used to add labels on issues + issues: write + # Used to add labels on PRs + pull-requests: write + steps: + - name: Label PR as React Core Team + uses: actions/github-script@v7 + with: + script: | + github.rest.issues.addLabels({ + owner: context.repo.owner, + repo: context.repo.repo, + issue_number: ${{ github.event.number }}, + labels: ['React Core Team'] + }); diff --git a/.gitignore b/.gitignore index d8bec488b..45ef7d278 100644 --- a/.gitignore +++ b/.gitignore @@ -36,3 +36,19 @@ yarn-error.log* # external fonts public/fonts/**/Optimistic_*.woff2 +<<<<<<< HEAD +======= + +# rss +public/rss.xml + +# claude local settings +.claude/*.local.* +.claude/react/ + +# worktrees +.worktrees/ + +# Generated OG images (scripts/generateOgImages.mjs) +public/images/og/ +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca diff --git a/package.json b/package.json index 932ad2582..1d9e3e8fd 100644 --- a/package.json +++ b/package.json @@ -6,9 +6,16 @@ "scripts": { "analyze": "ANALYZE=true next build", "dev": "next-remote-watch ./src/content", +<<<<<<< HEAD "build": "next build && node --experimental-modules ./scripts/downloadFonts.mjs", "lint": "next lint", "lint:fix": "next lint --fix", +======= + "prebuild:rsc": "node scripts/buildRscWorker.mjs", + "build": "node scripts/buildRscWorker.mjs && next build && node --experimental-modules ./scripts/downloadFonts.mjs && node ./scripts/generateOgImages.mjs", + "lint": "next lint && eslint \"src/content/**/*.md\"", + "lint:fix": "next lint --fix && eslint \"src/content/**/*.md\" --fix", +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca "format:source": "prettier --config .prettierrc --write \"{plugins,src}/**/*.{js,ts,jsx,tsx,css}\"", "nit:source": "prettier --config .prettierrc --list-different \"{plugins,src}/**/*.{js,ts,jsx,tsx,css}\"", "prettier": "yarn format:source", @@ -45,6 +52,7 @@ "@babel/plugin-transform-modules-commonjs": "^7.18.6", "@babel/preset-react": "^7.18.6", "@mdx-js/mdx": "^2.1.3", + "@resvg/resvg-js": "^2.6.2", "@types/body-scroll-lock": "^2.6.1", "@types/classnames": "^2.2.10", "@types/debounce": "^1.2.1", @@ -91,6 +99,7 @@ "retext": "^7.0.1", "retext-smartypants": "^4.0.0", "rss": "^1.2.2", + "satori": "^0.26.0", "tailwindcss": "^3.4.1", "typescript": "^4.0.2", "unist-util-visit": "^2.0.3", diff --git a/public/fonts/Optimistic_Display_W_Bd.ttf b/public/fonts/Optimistic_Display_W_Bd.ttf new file mode 100644 index 000000000..9d0cff450 Binary files /dev/null and b/public/fonts/Optimistic_Display_W_Bd.ttf differ diff --git a/public/fonts/Optimistic_Display_W_Md.ttf b/public/fonts/Optimistic_Display_W_Md.ttf new file mode 100644 index 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path.join(__dirname, '../src/content'); +const PUBLIC_DIR = path.join(__dirname, '../public'); +const fileCache = new Map(); +const anchorMap = new Map(); // Map<filepath, Set<anchorId>> +const contributorMap = new Map(); // Map<anchorId, URL> +const redirectMap = new Map(); // Map<source, destination> +let errorCodes = new Set(); + +async function readFileWithCache(filePath) { + if (!fileCache.has(filePath)) { + try { + const content = await fs.promises.readFile(filePath, 'utf8'); + fileCache.set(filePath, content); + } catch (error) { + throw new Error(`Failed to read file ${filePath}: ${error.message}`); + } + } + return fileCache.get(filePath); +} + +async function fileExists(filePath) { + try { + await fs.promises.access(filePath, fs.constants.R_OK); + return true; + } catch { + return false; + } +} + +function getMarkdownFiles() { + // Convert Windows paths to POSIX for globby compatibility + const baseDir = CONTENT_DIR.replace(/\\/g, '/'); + const patterns = [ + path.posix.join(baseDir, '**/*.md'), + path.posix.join(baseDir, '**/*.mdx'), + ]; + return globby.sync(patterns); +} + +function extractAnchorsFromContent(content) { + const anchors = new Set(); + + // MDX-style heading IDs: {/*anchor-id*/} + const mdxPattern = /\{\/\*([a-zA-Z0-9-_]+)\*\/\}/g; + let match; + while ((match = mdxPattern.exec(content)) !== null) { + anchors.add(match[1].toLowerCase()); + } + + // HTML id attributes + const htmlIdPattern = /\sid=["']([a-zA-Z0-9-_]+)["']/g; + while ((match = htmlIdPattern.exec(content)) !== null) { + anchors.add(match[1].toLowerCase()); + } + + // Markdown heading with explicit ID: ## Heading {#anchor-id} + const markdownHeadingPattern = /^#+\s+.*\{#([a-zA-Z0-9-_]+)\}/gm; + while ((match = markdownHeadingPattern.exec(content)) !== null) { + anchors.add(match[1].toLowerCase()); + } + + return anchors; +} + +async function buildAnchorMap(files) { + for (const filePath of files) { + const content = await readFileWithCache(filePath); + const anchors = extractAnchorsFromContent(content); + if (anchors.size > 0) { + anchorMap.set(filePath, anchors); + } + } +} + +function extractLinksFromContent(content) { + const linkPattern = /\[([^\]]*)\]\(([^)]+)\)/g; + const links = []; + let match; + + while ((match = linkPattern.exec(content)) !== null) { + const [, linkText, linkUrl] = match; + if (linkUrl.startsWith('/') && !linkUrl.startsWith('//')) { + const lines = content.substring(0, match.index).split('\n'); + const line = lines.length; + const lastLineStart = + lines.length > 1 ? content.lastIndexOf('\n', match.index - 1) + 1 : 0; + const column = match.index - lastLineStart + 1; + + links.push({ + text: linkText, + url: linkUrl, + line, + column, + }); + } + } + + return links; +} + +async function findTargetFile(urlPath) { + // Check if it's an image or static asset that might be in the public directory + const imageExtensions = [ + '.png', + '.jpg', + '.jpeg', + '.gif', + '.svg', + '.ico', + '.webp', + ]; + const hasImageExtension = imageExtensions.some((ext) => + urlPath.toLowerCase().endsWith(ext) + ); + + if (hasImageExtension || urlPath.includes('.')) { + // Check in public directory (with and without leading slash) + const publicPaths = [ + path.join(PUBLIC_DIR, urlPath), + path.join(PUBLIC_DIR, urlPath.substring(1)), + ]; + + for (const p of publicPaths) { + if (await fileExists(p)) { + return p; + } + } + } + + const possiblePaths = [ + path.join(CONTENT_DIR, urlPath + '.md'), + path.join(CONTENT_DIR, urlPath + '.mdx'), + path.join(CONTENT_DIR, urlPath, 'index.md'), + path.join(CONTENT_DIR, urlPath, 'index.mdx'), + // Without leading slash + path.join(CONTENT_DIR, urlPath.substring(1) + '.md'), + path.join(CONTENT_DIR, urlPath.substring(1) + '.mdx'), + path.join(CONTENT_DIR, urlPath.substring(1), 'index.md'), + path.join(CONTENT_DIR, urlPath.substring(1), 'index.mdx'), + ]; + + for (const p of possiblePaths) { + if (await fileExists(p)) { + return p; + } + } + return null; +} + +async function validateLink(link) { + const urlAnchorPattern = /#([a-zA-Z0-9-_]+)$/; + const anchorMatch = link.url.match(urlAnchorPattern); + const urlWithoutAnchor = link.url.replace(urlAnchorPattern, ''); + + if (urlWithoutAnchor === '/') { + return {valid: true}; + } + + // Check for redirects + if (redirectMap.has(urlWithoutAnchor)) { + const redirectDestination = redirectMap.get(urlWithoutAnchor); + if ( + redirectDestination.startsWith('http://') || + redirectDestination.startsWith('https://') + ) { + return {valid: true}; + } + const redirectedLink = { + ...link, + url: redirectDestination + (anchorMatch ? anchorMatch[0] : ''), + }; + return validateLink(redirectedLink); + } + + // Check if it's an error code link + const errorCodeMatch = urlWithoutAnchor.match(/^\/errors\/(\d+)$/); + if (errorCodeMatch) { + const code = errorCodeMatch[1]; + if (!errorCodes.has(code)) { + return { + valid: false, + reason: `Error code ${code} not found in React error codes`, + }; + } + return {valid: true}; + } + + // Check if it's a contributor link on the team or acknowledgements page + if ( + anchorMatch && + (urlWithoutAnchor === '/community/team' || + urlWithoutAnchor === '/community/acknowledgements') + ) { + const anchorId = anchorMatch[1].toLowerCase(); + if (contributorMap.has(anchorId)) { + const correctUrl = contributorMap.get(anchorId); + if (correctUrl !== link.url) { + return { + valid: false, + reason: `Contributor link should be updated to: ${correctUrl}`, + }; + } + return {valid: true}; + } else { + return { + valid: false, + reason: `Contributor link not found`, + }; + } + } + + const targetFile = await findTargetFile(urlWithoutAnchor); + + if (!targetFile) { + return { + valid: false, + reason: `Target file not found for: ${urlWithoutAnchor}`, + }; + } + + // Only check anchors for content files, not static assets + if (anchorMatch && targetFile.startsWith(CONTENT_DIR)) { + const anchorId = anchorMatch[1].toLowerCase(); + + // TODO handle more special cases. These are usually from custom MDX components that include + // a Heading from src/components/MDX/Heading.tsx which automatically injects an anchor tag. + switch (anchorId) { + case 'challenges': + case 'recap': { + return {valid: true}; + } + } + + const fileAnchors = anchorMap.get(targetFile); + + if (!fileAnchors || !fileAnchors.has(anchorId)) { + return { + valid: false, + reason: `Anchor #${anchorMatch[1]} not found in ${path.relative( + CONTENT_DIR, + targetFile + )}`, + }; + } + } + + return {valid: true}; +} + +async function processFile(filePath) { + const content = await readFileWithCache(filePath); + const links = extractLinksFromContent(content); + const deadLinks = []; + + for (const link of links) { + const result = await validateLink(link); + if (!result.valid) { + deadLinks.push({ + file: path.relative(process.cwd(), filePath), + line: link.line, + column: link.column, + text: link.text, + url: link.url, + reason: result.reason, + }); + } + } + + return {deadLinks, totalLinks: links.length}; +} + +async function buildContributorMap() { + const teamFile = path.join(CONTENT_DIR, 'community/team.md'); + const teamContent = await readFileWithCache(teamFile); + + const teamMemberPattern = /<TeamMember[^>]*permalink=["']([^"']+)["']/g; + let match; + + while ((match = teamMemberPattern.exec(teamContent)) !== null) { + const permalink = match[1]; + contributorMap.set(permalink, `/community/team#${permalink}`); + } + + const ackFile = path.join(CONTENT_DIR, 'community/acknowledgements.md'); + const ackContent = await readFileWithCache(ackFile); + const contributorPattern = /\*\s*\[([^\]]+)\]\(([^)]+)\)/g; + + while ((match = contributorPattern.exec(ackContent)) !== null) { + const name = match[1]; + const url = match[2]; + const hyphenatedName = name.toLowerCase().replace(/\s+/g, '-'); + if (!contributorMap.has(hyphenatedName)) { + contributorMap.set(hyphenatedName, url); + } + } +} + +async function fetchErrorCodes() { + try { + const response = await fetch( + 'https://raw.githubusercontent.com/react/react/main/scripts/error-codes/codes.json' + ); + if (!response.ok) { + throw new Error(`Failed to fetch error codes: ${response.status}`); + } + const codes = await response.json(); + errorCodes = new Set(Object.keys(codes)); + console.log(chalk.gray(`Fetched ${errorCodes.size} React error codes`)); + } catch (error) { + throw new Error(`Failed to fetch error codes: ${error.message}`); + } +} + +async function buildRedirectsMap() { + try { + const vercelConfigPath = path.join(__dirname, '../vercel.json'); + const vercelConfig = JSON.parse( + await fs.promises.readFile(vercelConfigPath, 'utf8') + ); + + if (vercelConfig.redirects) { + for (const redirect of vercelConfig.redirects) { + redirectMap.set(redirect.source, redirect.destination); + } + console.log( + chalk.gray(`Loaded ${redirectMap.size} redirects from vercel.json`) + ); + } + } catch (error) { + console.log( + chalk.yellow( + `Warning: Could not load redirects from vercel.json: ${error.message}\n` + ) + ); + } +} + +async function main() { + const files = getMarkdownFiles(); + console.log(chalk.gray(`Checking ${files.length} markdown files...`)); + + await fetchErrorCodes(); + await buildRedirectsMap(); + await buildContributorMap(); + await buildAnchorMap(files); + + const filePromises = files.map((filePath) => processFile(filePath)); + const results = await Promise.all(filePromises); + const deadLinks = results.flatMap((r) => r.deadLinks); + const totalLinks = results.reduce((sum, r) => sum + r.totalLinks, 0); + + if (deadLinks.length > 0) { + console.log('\n'); + for (const link of deadLinks) { + console.log(chalk.yellow(`${link.file}:${link.line}:${link.column}`)); + console.log(chalk.reset(` Link text: ${link.text}`)); + console.log(chalk.reset(` URL: ${link.url}`)); + console.log(` ${chalk.red('✗')} ${chalk.red(link.reason)}\n`); + } + + console.log( + chalk.red( + `\nFound ${deadLinks.length} dead link${ + deadLinks.length > 1 ? 's' : '' + } out of ${totalLinks} total links\n` + ) + ); + process.exit(1); + } + + console.log(chalk.green(`\n✓ All ${totalLinks} links are valid!\n`)); + process.exit(0); +} + +main().catch((error) => { + console.log(chalk.red(`Error: ${error.message}`)); + process.exit(1); +}); diff --git a/scripts/generateOgImages.mjs b/scripts/generateOgImages.mjs new file mode 100644 index 000000000..937727a1c --- /dev/null +++ b/scripts/generateOgImages.mjs @@ -0,0 +1,219 @@ +/** + * Copyright (c) Meta Platforms, Inc. and affiliates. + * + * This source code is licensed under the MIT license found in the + * LICENSE file in the root directory of this source tree. + */ + +// Generates a static OG image for every content page, so social +// cards show the page title without any runtime image generation. +// Run after `next build` (see the `build` script in package.json). + +import fs from 'fs'; +import path from 'path'; +import satori from 'satori'; +import {Resvg} from '@resvg/resvg-js'; +import matter from 'gray-matter'; + +const ROOT = process.cwd(); +const CONTENT_DIR = path.join(ROOT, 'src', 'content'); +const OUT_DIR = path.join(ROOT, 'public', 'images', 'og'); +const CONCURRENCY = 8; + +const SECTION_LABELS = { + learn: 'Learn React', + reference: 'API Reference', + community: 'Community', + blog: 'Blog', +}; + +const bold = fs.readFileSync( + path.join(ROOT, 'public', 'fonts', 'Optimistic_Display_W_Bd.ttf') +); +const medium = fs.readFileSync( + path.join(ROOT, 'public', 'fonts', 'Optimistic_Display_W_Md.ttf') +); + +function el(type, style, children) { + return {type, props: {style, children}}; +} + +function card(title, pagePath) { + const section = pagePath.split('/')[1] ?? ''; + const label = SECTION_LABELS[section] ?? 'React'; + const logo = { + type: 'svg', + props: { + width: 80, + height: 72, + viewBox: '-10.5 -9.45 21 18.9', + fill: 'none', + children: [ + {type: 'circle', props: {cx: 0, cy: 0, r: 2, fill: '#58c4dc'}}, + { + type: 'g', + props: { + stroke: '#58c4dc', + strokeWidth: 1, + fill: 'none', + children: [ + {type: 'ellipse', props: {rx: 10, ry: 4.5}}, + { + type: 'ellipse', + props: {rx: 10, ry: 4.5, transform: 'rotate(60)'}, + }, + { + type: 'ellipse', + props: {rx: 10, ry: 4.5, transform: 'rotate(120)'}, + }, + ], + }, + }, + ], + }, + }; + return el( + 'div', + { + width: '100%', + height: '100%', + display: 'flex', + flexDirection: 'column', + padding: '72px 80px', + backgroundColor: '#23272f', + backgroundImage: + 'radial-gradient(circle at 25% 30%, #343a46 0%, #23272f 55%)', + }, + [ + el('div', {display: 'flex', alignItems: 'center', gap: '20px'}, [ + logo, + el( + 'div', + { + fontSize: 48, + fontFamily: 'Optimistic Display Bold', + color: '#f6f7f9', + }, + 'React' + ), + ]), + el( + 'div', + { + flexGrow: 1, + display: 'flex', + alignItems: 'center', + fontSize: title.length > 24 ? 72 : 96, + fontFamily: 'Optimistic Display Bold', + color: '#f6f7f9', + lineHeight: 1.1, + wordBreak: 'break-word', + }, + title + ), + el( + 'div', + { + fontSize: 40, + fontFamily: 'Optimistic Display Medium', + color: '#99a1b3', + }, + label + ), + ] + ); +} + +async function renderCard(title, pagePath) { + const svg = await satori(card(title, pagePath), { + width: 1200, + height: 630, + fonts: [ + { + name: 'Optimistic Display Bold', + data: bold, + weight: 700, + style: 'normal', + }, + { + name: 'Optimistic Display Medium', + data: medium, + weight: 500, + style: 'normal', + }, + ], + }); + return new Resvg(svg, {fitTo: {mode: 'width', value: 1200}}).render().asPng(); +} + +function collectSidebarTitles() { + const titles = new Map(); + for (const name of fs.readdirSync(path.join(ROOT, 'src'))) { + if (!/^sidebar.*\.json$/.test(name)) continue; + const walk = (node) => { + if (node.path && node.title) { + titles.set(node.path, node.title); + } + for (const child of node.routes ?? []) walk(child); + }; + walk(JSON.parse(fs.readFileSync(path.join(ROOT, 'src', name), 'utf8'))); + } + return titles; +} + +const sidebarTitles = collectSidebarTitles(); + +function collectPages(dir, out) { + for (const entry of fs.readdirSync(dir, {withFileTypes: true})) { + const full = path.join(dir, entry.name); + if (entry.isDirectory()) { + collectPages(full, out); + } else if (entry.name.endsWith('.md')) { + const rel = path.relative(CONTENT_DIR, full).replace(/\.md$/, ''); + const segments = rel.split(path.sep); + if (segments[segments.length - 1] === 'index') { + segments.pop(); + } + const pagePath = '/' + segments.join('/'); + if (pagePath === '/' || pagePath.startsWith('/errors')) { + continue; + } + const {data} = matter(fs.readFileSync(full, 'utf8')); + const title = data.title ?? sidebarTitles.get(pagePath); + if (title) { + out.push({title: String(title), pagePath}); + } + } + } + return out; +} + +export function ogImageFileName(pagePath) { + return pagePath.replace(/^\//, '').replace(/\//g, '-') + '.png'; +} + +async function main() { + const pages = collectPages(CONTENT_DIR, []); + fs.mkdirSync(OUT_DIR, {recursive: true}); + let done = 0; + const queue = [...pages]; + async function worker() { + for (;;) { + const page = queue.shift(); + if (!page) return; + const png = await renderCard(page.title, page.pagePath); + fs.writeFileSync(path.join(OUT_DIR, ogImageFileName(page.pagePath)), png); + done++; + if (done % 100 === 0) { + console.log(`og-images: ${done}/${pages.length}`); + } + } + } + await Promise.all(Array.from({length: CONCURRENCY}, worker)); + console.log(`og-images: generated ${done} images in public/images/og`); +} + +main().catch((error) => { + console.error(error); + process.exit(1); +}); diff --git a/src/components/ButtonLink.tsx b/src/components/ButtonLink.tsx index 15ab83f2b..3d11fe3bd 100644 --- a/src/components/ButtonLink.tsx +++ b/src/components/ButtonLink.tsx @@ -26,7 +26,12 @@ function ButtonLink({ className, 'active:scale-[.98] transition-transform inline-flex font-bold items-center outline-none focus:outline-none focus-visible:outline focus-visible:outline-link focus:outline-offset-2 focus-visible:dark:focus:outline-link-dark leading-snug', { +<<<<<<< HEAD 'bg-link text-white hover:bg-opacity-80': type === 'primary', +======= + 'bg-link text-white dark:bg-brand-dark dark:text-gray-90 hover:bg-opacity-80': + type === 'primary', +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca 'text-primary dark:text-primary-dark shadow-secondary-button-stroke dark:shadow-secondary-button-stroke-dark hover:bg-gray-40/5 active:bg-gray-40/10 hover:dark:bg-gray-60/5 active:dark:bg-gray-60/10': type === 'secondary', 'text-lg py-3 rounded-full px-4 sm:px-6': size === 'lg', diff --git a/src/components/Layout/Footer.tsx b/src/components/Layout/Footer.tsx index 26bdf6711..6d923f526 100644 --- a/src/components/Layout/Footer.tsx +++ b/src/components/Layout/Footer.tsx @@ -312,7 +312,7 @@ export function Footer() { <FooterLink href="/community" isHeader={true}> Community </FooterLink> - <FooterLink href="https://github.com/facebook/react/blob/main/CODE_OF_CONDUCT.md"> + <FooterLink href="https://github.com/react/react/blob/main/CODE_OF_CONDUCT.md"> Code of Conduct </FooterLink> <FooterLink href="/community/team">Meet the Team</FooterLink> @@ -348,7 +348,7 @@ export function Footer() { </ExternalLink> <ExternalLink aria-label="React on Github" - href="https://github.com/facebook/react" + href="https://github.com/react/react" className={socialLinkClasses}> <IconGitHub /> </ExternalLink> diff --git a/src/components/Layout/Page.tsx b/src/components/Layout/Page.tsx index 5194279c2..6c7517c1c 100644 --- a/src/components/Layout/Page.tsx +++ b/src/components/Layout/Page.tsx @@ -114,7 +114,18 @@ export function Page({children, toc, routeTree, meta, section}: PageProps) { title={title} titleForTitleTag={meta.titleForTitleTag} isHomePage={isHomePage} - image={`/images/og-` + section + '.png'} + image={ + // OG images are generated per page at build time by + // scripts/generateOgImages.mjs. Pages without a generated + // card (home, errors, 404, 500) use the static section image. + isHomePage || + !title || + cleanedPath.startsWith('/errors') || + cleanedPath === '/404' || + cleanedPath === '/500' + ? `/images/og-${section ?? 'unknown'}.png` + : `/images/og/${cleanedPath.slice(1).replace(/\//g, '-')}.png` + } searchOrder={searchOrder} /> <SocialBanner /> diff --git a/src/components/Layout/Toc.tsx b/src/components/Layout/Toc.tsx index 5308c602c..d7d200156 100644 --- a/src/components/Layout/Toc.tsx +++ b/src/components/Layout/Toc.tsx @@ -4,6 +4,7 @@ import cx from 'classnames'; import {useTocHighlight} from './useTocHighlight'; +import {IsInTocContext} from '../MDX/TocContext'; import type {Toc} from '../MDX/TocContext'; export function Toc({headings}: {headings: Toc}) { @@ -25,37 +26,39 @@ export function Toc({headings}: {headings: Toc}) { overscrollBehavior: 'contain', }}> <ul className="space-y-2 pb-16"> - {headings.length > 0 && - headings.map((h, i) => { - if (!h.url && process.env.NODE_ENV === 'development') { - console.error('Heading does not have URL'); - } - return ( - <li - key={`heading-${h.url}-${i}`} - className={cx( - 'text-sm px-2 rounded-s-xl', - selectedIndex === i - ? 'bg-highlight dark:bg-highlight-dark' - : null, - { - 'ps-4': h?.depth === 3, - hidden: h.depth && h.depth > 3, - } - )}> - <a + <IsInTocContext.Provider value={true}> + {headings.length > 0 && + headings.map((h, i) => { + if (!h.url && process.env.NODE_ENV === 'development') { + console.error('Heading does not have URL'); + } + return ( + <li + key={`heading-${h.url}-${i}`} className={cx( + 'text-sm px-2 rounded-s-xl', selectedIndex === i - ? 'text-link dark:text-link-dark font-bold' - : 'text-secondary dark:text-secondary-dark', - 'block hover:text-link dark:hover:text-link-dark leading-normal py-2' - )} - href={h.url}> - {h.text} - </a> - </li> - ); - })} + ? 'bg-highlight dark:bg-highlight-dark' + : null, + { + 'ps-4': h?.depth === 3, + hidden: h.depth && h.depth > 3, + } + )}> + <a + className={cx( + selectedIndex === i + ? 'text-link dark:text-link-dark font-bold' + : 'text-secondary dark:text-secondary-dark', + 'block hover:text-link dark:hover:text-link-dark leading-normal py-2' + )} + href={h.url}> + {h.text} + </a> + </li> + ); + })} + </IsInTocContext.Provider> </ul> </div> </nav> diff --git a/src/components/Layout/TopNav/TopNav.tsx b/src/components/Layout/TopNav/TopNav.tsx index b6e276ff7..7f65055a8 100644 --- a/src/components/Layout/TopNav/TopNav.tsx +++ b/src/components/Layout/TopNav/TopNav.tsx @@ -330,7 +330,19 @@ export default function TopNav({ </div> <div className="flex"> <Link +<<<<<<< HEAD href="https://github.com/facebook/react/releases" +======= + href="/community/translations" + aria-label="Translations" + className="active:scale-95 transition-transform flex w-12 h-12 rounded-full items-center justify-center hover:bg-primary/5 hover:dark:bg-primary-dark/5 outline-link"> + {languageIcon} + </Link> + </div> + <div className="flex"> + <Link + href="https://github.com/react/react/releases" +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca target="_blank" rel="noreferrer noopener" aria-label="Open on GitHub" diff --git a/src/components/MDX/MDXComponents.tsx b/src/components/MDX/MDXComponents.tsx index 76bf86eaa..4a75ceb47 100644 --- a/src/components/MDX/MDXComponents.tsx +++ b/src/components/MDX/MDXComponents.tsx @@ -28,7 +28,7 @@ import YouWillLearnCard from './YouWillLearnCard'; import {Challenges, Hint, Solution} from './Challenges'; import {IconNavArrow} from '../Icon/IconNavArrow'; import ButtonLink from 'components/ButtonLink'; -import {TocContext} from './TocContext'; +import {TocContext, IsInTocContext} from './TocContext'; import type {Toc, TocItem} from './TocContext'; import {TeamMember} from './TeamMember'; @@ -94,10 +94,102 @@ const Canary = ({children}: {children: React.ReactNode}) => ( <ExpandableCallout type="canary">{children}</ExpandableCallout> ); +<<<<<<< HEAD const Blockquote = ({ children, ...props }: JSX.IntrinsicElements['blockquote']) => { +======= +const RC = ({children}: {children: React.ReactNode}) => ( + <ExpandableCallout type="rc">{children}</ExpandableCallout> +); + +const Experimental = ({children}: {children: React.ReactNode}) => ( + <ExpandableCallout type="experimental">{children}</ExpandableCallout> +); + +const NextMajor = ({children}: {children: React.ReactNode}) => ( + <ExpandableCallout type="major">{children}</ExpandableCallout> +); + +const RSC = ({children}: {children: React.ReactNode}) => ( + <ExpandableCallout type="rsc">{children}</ExpandableCallout> +); + +const CanaryBadge = ({title}: {title: string}) => { + const isInToc = useContext(IsInTocContext); + if (isInToc) { + return ( + <IconCanary + size="s" + title={title} + className="inline me-1 mb-0.5 text-gray-60 dark:text-gray-10" + /> + ); + } + return ( + <span + title={title} + className={ + 'text-base font-display px-1 py-0.5 font-bold bg-gray-10 dark:bg-gray-60 text-gray-60 dark:text-gray-10 rounded' + }> + <IconCanary + size="s" + className={'inline me-1 mb-0.5 text-sm text-gray-60 dark:text-gray-10'} + /> + Canary only + </span> + ); +}; + +const ExperimentalBadge = ({title}: {title: string}) => { + const isInToc = useContext(IsInTocContext); + if (isInToc) { + return ( + <IconExperimental + size="s" + title={title} + className="inline me-1 mb-0.5 text-gray-60 dark:text-gray-10" + /> + ); + } + return ( + <span + title={title} + className={ + 'text-base font-display px-1 py-0.5 font-bold bg-gray-10 dark:bg-gray-60 text-gray-60 dark:text-gray-10 rounded' + }> + <IconExperimental + size="s" + className={'inline me-1 mb-0.5 text-sm text-gray-60 dark:text-gray-10'} + /> + Experimental only + </span> + ); +}; + +const NextMajorBadge = ({title}: {title: string}) => ( + <span + title={title} + className={ + 'text-base font-display px-2 py-0.5 font-bold bg-blue-10 dark:bg-blue-60 text-gray-60 dark:text-gray-10 rounded' + }> + React 19 + </span> +); + +const RSCBadge = ({title}: {title: string}) => ( + <span + title={title} + className={ + 'text-base font-display px-2 py-0.5 font-bold bg-blue-10 dark:bg-blue-50 text-gray-60 dark:text-gray-10 rounded' + }> + RSC + </span> +); + +const Blockquote = ({children, ...props}: HTMLAttributes<HTMLQuoteElement>) => { +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca return ( <blockquote className="mdx-blockquote py-4 px-8 my-8 shadow-inner-border dark:shadow-inner-border-dark bg-highlight dark:bg-highlight-dark bg-opacity-50 rounded-2xl leading-6 flex relative" @@ -349,7 +441,11 @@ function InlineToc() { if (root.children.length < 2) { return null; } - return <InlineTocItem items={root.children} />; + return ( + <IsInTocContext.Provider value={true}> + <InlineTocItem items={root.children} /> + </IsInTocContext.Provider> + ); } function InlineTocItem({items}: {items: Array<NestedTocNode>}) { diff --git a/src/components/MDX/Sandpack/DownloadButton.tsx b/src/components/MDX/Sandpack/DownloadButton.tsx index 94cf13ddc..22f1e9368 100644 --- a/src/components/MDX/Sandpack/DownloadButton.tsx +++ b/src/components/MDX/Sandpack/DownloadButton.tsx @@ -12,7 +12,7 @@ let supportsImportMap = false; function subscribe(cb: () => void) { // This shouldn't actually need to update, but this works around - // https://github.com/facebook/react/issues/26095 + // https://github.com/react/react/issues/26095 let timeout = setTimeout(() => { supportsImportMap = (HTMLScriptElement as any).supports && diff --git a/src/components/MDX/TeamMember.tsx b/src/components/MDX/TeamMember.tsx index c9e83ebc6..3c20268f1 100644 --- a/src/components/MDX/TeamMember.tsx +++ b/src/components/MDX/TeamMember.tsx @@ -15,12 +15,48 @@ interface TeamMemberProps { name: string; title: string; permalink: string; - children: React.ReactNode; + children?: React.ReactNode; photo: string; twitter?: string; threads?: string; github?: string; personal?: string; + // Comma-separated list of working groups. Suffix a group with `*` to mark + // that the member represents it on the Leadership Council, e.g. "Fiber*, DOM". + group?: string; +} + +function GroupBadges({group}: {group: string}) { + const groups = group + .split(',') + .map((g) => g.trim()) + .filter(Boolean); + if (groups.length === 0) { + return null; + } + return ( + <div className="flex flex-row flex-wrap gap-2 my-3"> + {groups.map((g) => { + const isLead = g.endsWith('*'); + const label = isLead ? g.slice(0, -1).trim() : g; + return ( + <span + key={g} + className="inline-flex items-center rounded-full bg-blue-10 dark:bg-gray-80 text-link dark:text-link-dark px-3 py-1 text-sm font-medium whitespace-nowrap"> + {label} + {isLead && ( + <span + className="ps-1 text-yellow-50" + aria-label="Leadership Council" + title="Leadership Council"> + ★ + </span> + )} + </span> + ); + })} + </div> + ); } // TODO: good alt text for images/links @@ -34,7 +70,9 @@ export function TeamMember({ twitter, threads, personal, + group, }: TeamMemberProps) { +<<<<<<< HEAD if (name == null || title == null || permalink == null || children == null) { throw new Error( 'Expected name, title, permalink, and children for ' + name ?? @@ -42,6 +80,11 @@ export function TeamMember({ permalink ?? 'unknown' ); +======= + if (name == null || title == null || permalink == null) { + const identifier = name ?? title ?? permalink ?? 'unknown'; + throw new Error(`Expected name, title, and permalink for ${identifier}`); +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca } return ( <div className="pb-6 sm:pb-10"> @@ -61,6 +104,7 @@ export function TeamMember({ {name} </H3> {title && <div>{title}</div>} + {group && <GroupBadges group={group} />} {children} <div className="sm:flex sm:flex-row flex-wrap"> {twitter && ( diff --git a/src/components/MDX/TocContext.tsx b/src/components/MDX/TocContext.tsx index 8aeead370..0b746108c 100644 --- a/src/components/MDX/TocContext.tsx +++ b/src/components/MDX/TocContext.tsx @@ -13,3 +13,6 @@ export type TocItem = { export type Toc = Array<TocItem>; export const TocContext = createContext<Toc>([]); + +// Lets badge components render compactly when inside the table of contents. +export const IsInTocContext = createContext(false); diff --git a/src/content/blog/2021/06/08/the-plan-for-react-18.md b/src/content/blog/2021/06/08/the-plan-for-react-18.md index 0bf744c1d..c2f0b5189 100644 --- a/src/content/blog/2021/06/08/the-plan-for-react-18.md +++ b/src/content/blog/2021/06/08/the-plan-for-react-18.md @@ -48,7 +48,7 @@ Everyone can read the discussions in the [React 18 Working Group repo](https://g Because we expect an initial surge of interest in the Working Group, only invited members will be allowed to create or comment on threads. However, the threads are fully visible to the public, so everyone has access to the same information. We believe this is a good compromise between creating a productive environment for working group members, while maintaining transparency with the wider community. -As always, you can submit bug reports, questions, and general feedback to our [issue tracker](https://github.com/facebook/react/issues). +As always, you can submit bug reports, questions, and general feedback to our [issue tracker](https://github.com/react/react/issues). ## How to try React 18 Alpha today {/*how-to-try-react-18-alpha-today*/} diff --git a/src/content/blog/2022/03/08/react-18-upgrade-guide.md b/src/content/blog/2022/03/08/react-18-upgrade-guide.md index 66da896ec..677c752bd 100644 --- a/src/content/blog/2022/03/08/react-18-upgrade-guide.md +++ b/src/content/blog/2022/03/08/react-18-upgrade-guide.md @@ -10,7 +10,7 @@ March 08, 2022 by [Rick Hanlon](https://twitter.com/rickhanlonii) As we shared in the [release post](/blog/2022/03/29/react-v18), React 18 introduces features powered by our new concurrent renderer, with a gradual adoption strategy for existing applications. In this post, we will guide you through the steps for upgrading to React 18. -Please [report any issues](https://github.com/facebook/react/issues/new/choose) you encounter while upgrading to React 18. +Please [report any issues](https://github.com/react/react/issues/new/choose) you encounter while upgrading to React 18. </Intro> @@ -314,8 +314,8 @@ If you need to support Internet Explorer we recommend you stay with React 17. * **Components can now render `undefined`:** React no longer warns if you return `undefined` from a component. This makes the allowed component return values consistent with values that are allowed in the middle of a component tree. We suggest to use a linter to prevent mistakes like forgetting a `return` statement before JSX. * **In tests, `act` warnings are now opt-in:** If you're running end-to-end tests, the `act` warnings are unnecessary. We've introduced an [opt-in](https://github.com/reactwg/react-18/discussions/102) mechanism so you can enable them only for unit tests where they are useful and beneficial. -* **No warning about `setState` on unmounted components:** Previously, React warned about memory leaks when you call `setState` on an unmounted component. This warning was added for subscriptions, but people primarily run into it in scenarios where setting state is fine, and workarounds make the code worse. We've [removed](https://github.com/facebook/react/pull/22114) this warning. -* **No suppression of console logs:** When you use Strict Mode, React renders each component twice to help you find unexpected side effects. In React 17, we've suppressed console logs for one of the two renders to make the logs easier to read. In response to [community feedback](https://github.com/facebook/react/issues/21783) about this being confusing, we've removed the suppression. Instead, if you have React DevTools installed, the second log's renders will be displayed in grey, and there will be an option (off by default) to suppress them completely. +* **No warning about `setState` on unmounted components:** Previously, React warned about memory leaks when you call `setState` on an unmounted component. This warning was added for subscriptions, but people primarily run into it in scenarios where setting state is fine, and workarounds make the code worse. We've [removed](https://github.com/react/react/pull/22114) this warning. +* **No suppression of console logs:** When you use Strict Mode, React renders each component twice to help you find unexpected side effects. In React 17, we've suppressed console logs for one of the two renders to make the logs easier to read. In response to [community feedback](https://github.com/react/react/issues/21783) about this being confusing, we've removed the suppression. Instead, if you have React DevTools installed, the second log's renders will be displayed in grey, and there will be an option (off by default) to suppress them completely. * **Improved memory usage:** React now cleans up more internal fields on unmount, making the impact from unfixed memory leaks that may exist in your application code less severe. ### React DOM Server {/*react-dom-server*/} @@ -325,4 +325,4 @@ If you need to support Internet Explorer we recommend you stay with React 17. ## Changelog {/*changelog*/} -You can view the [full changelog here](https://github.com/facebook/react/blob/main/CHANGELOG.md). +You can view the [full changelog here](https://github.com/react/react/blob/main/CHANGELOG.md). diff --git a/src/content/blog/2022/03/29/react-v18.md b/src/content/blog/2022/03/29/react-v18.md index 743404c1a..3e4c4db6a 100644 --- a/src/content/blog/2022/03/29/react-v18.md +++ b/src/content/blog/2022/03/29/react-v18.md @@ -267,75 +267,75 @@ See [How to Upgrade to React 18](/blog/2022/03/08/react-18-upgrade-guide) for st ### React {/*react*/} -* Add `useTransition` and `useDeferredValue` to separate urgent updates from transitions. ([#10426](https://github.com/facebook/react/pull/10426), [#10715](https://github.com/facebook/react/pull/10715), [#15593](https://github.com/facebook/react/pull/15593), [#15272](https://github.com/facebook/react/pull/15272), [#15578](https://github.com/facebook/react/pull/15578), [#15769](https://github.com/facebook/react/pull/15769), [#17058](https://github.com/facebook/react/pull/17058), [#18796](https://github.com/facebook/react/pull/18796), [#19121](https://github.com/facebook/react/pull/19121), [#19703](https://github.com/facebook/react/pull/19703), [#19719](https://github.com/facebook/react/pull/19719), [#19724](https://github.com/facebook/react/pull/19724), [#20672](https://github.com/facebook/react/pull/20672), [#20976](https://github.com/facebook/react/pull/20976) by [@acdlite](https://github.com/acdlite), [@lunaruan](https://github.com/lunaruan), [@rickhanlonii](https://github.com/rickhanlonii), and [@sebmarkbage](https://github.com/sebmarkbage)) -* Add `useId` for generating unique IDs. ([#17322](https://github.com/facebook/react/pull/17322), [#18576](https://github.com/facebook/react/pull/18576), [#22644](https://github.com/facebook/react/pull/22644), [#22672](https://github.com/facebook/react/pull/22672), [#21260](https://github.com/facebook/react/pull/21260) by [@acdlite](https://github.com/acdlite), [@lunaruan](https://github.com/lunaruan), and [@sebmarkbage](https://github.com/sebmarkbage)) -* Add `useSyncExternalStore` to help external store libraries integrate with React. ([#15022](https://github.com/facebook/react/pull/15022), [#18000](https://github.com/facebook/react/pull/18000), [#18771](https://github.com/facebook/react/pull/18771), [#22211](https://github.com/facebook/react/pull/22211), [#22292](https://github.com/facebook/react/pull/22292), [#22239](https://github.com/facebook/react/pull/22239), [#22347](https://github.com/facebook/react/pull/22347), [#23150](https://github.com/facebook/react/pull/23150) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), and [@drarmstr](https://github.com/drarmstr)) -* Add `startTransition` as a version of `useTransition` without pending feedback. ([#19696](https://github.com/facebook/react/pull/19696) by [@rickhanlonii](https://github.com/rickhanlonii)) -* Add `useInsertionEffect` for CSS-in-JS libraries. ([#21913](https://github.com/facebook/react/pull/21913) by [@rickhanlonii](https://github.com/rickhanlonii)) -* Make Suspense remount layout effects when content reappears. ([#19322](https://github.com/facebook/react/pull/19322), [#19374](https://github.com/facebook/react/pull/19374), [#19523](https://github.com/facebook/react/pull/19523), [#20625](https://github.com/facebook/react/pull/20625), [#21079](https://github.com/facebook/react/pull/21079) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), and [@lunaruan](https://github.com/lunaruan)) -* Make `<StrictMode>` re-run effects to check for restorable state. ([#19523](https://github.com/facebook/react/pull/19523) , [#21418](https://github.com/facebook/react/pull/21418) by [@bvaughn](https://github.com/bvaughn) and [@lunaruan](https://github.com/lunaruan)) -* Assume Symbols are always available. ([#23348](https://github.com/facebook/react/pull/23348) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Remove `object-assign` polyfill. ([#23351](https://github.com/facebook/react/pull/23351) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Remove unsupported `unstable_changedBits` API. ([#20953](https://github.com/facebook/react/pull/20953) by [@acdlite](https://github.com/acdlite)) -* Allow components to render undefined. ([#21869](https://github.com/facebook/react/pull/21869) by [@rickhanlonii](https://github.com/rickhanlonii)) -* Flush `useEffect` resulting from discrete events like clicks synchronously. ([#21150](https://github.com/facebook/react/pull/21150) by [@acdlite](https://github.com/acdlite)) -* Suspense `fallback={undefined}` now behaves the same as `null` and isn't ignored. ([#21854](https://github.com/facebook/react/pull/21854) by [@rickhanlonii](https://github.com/rickhanlonii)) -* Consider all `lazy()` resolving to the same component equivalent. ([#20357](https://github.com/facebook/react/pull/20357) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Don't patch console during first render. ([#22308](https://github.com/facebook/react/pull/22308) by [@lunaruan](https://github.com/lunaruan)) -* Improve memory usage. ([#21039](https://github.com/facebook/react/pull/21039) by [@bgirard](https://github.com/bgirard)) -* Improve messages if string coercion throws (Temporal.*, Symbol, etc.) ([#22064](https://github.com/facebook/react/pull/22064) by [@justingrant](https://github.com/justingrant)) -* Use `setImmediate` when available over `MessageChannel`. ([#20834](https://github.com/facebook/react/pull/20834) by [@gaearon](https://github.com/gaearon)) -* Fix context failing to propagate inside suspended trees. ([#23095](https://github.com/facebook/react/pull/23095) by [@gaearon](https://github.com/gaearon)) -* Fix `useReducer` observing incorrect props by removing the eager bailout mechanism. ([#22445](https://github.com/facebook/react/pull/22445) by [@josephsavona](https://github.com/josephsavona)) -* Fix `setState` being ignored in Safari when appending iframes. ([#23111](https://github.com/facebook/react/pull/23111) by [@gaearon](https://github.com/gaearon)) -* Fix a crash when rendering `ZonedDateTime` in the tree. ([#20617](https://github.com/facebook/react/pull/20617) by [@dimaqq](https://github.com/dimaqq)) -* Fix a crash when document is set to `null` in tests. ([#22695](https://github.com/facebook/react/pull/22695) by [@SimenB](https://github.com/SimenB)) -* Fix `onLoad` not triggering when concurrent features are on. ([#23316](https://github.com/facebook/react/pull/23316) by [@gnoff](https://github.com/gnoff)) -* Fix a warning when a selector returns `NaN`. ([#23333](https://github.com/facebook/react/pull/23333) by [@hachibeeDI](https://github.com/hachibeeDI)) -* Fix a crash when document is set to `null` in tests. ([#22695](https://github.com/facebook/react/pull/22695) by [@SimenB](https://github.com/SimenB)) -* Fix the generated license header. ([#23004](https://github.com/facebook/react/pull/23004) by [@vitaliemiron](https://github.com/vitaliemiron)) -* Add `package.json` as one of the entry points. ([#22954](https://github.com/facebook/react/pull/22954) by [@Jack](https://github.com/Jack-Works)) -* Allow suspending outside a Suspense boundary. ([#23267](https://github.com/facebook/react/pull/23267) by [@acdlite](https://github.com/acdlite)) -* Log a recoverable error whenever hydration fails. ([#23319](https://github.com/facebook/react/pull/23319) by [@acdlite](https://github.com/acdlite)) +* Add `useTransition` and `useDeferredValue` to separate urgent updates from transitions. ([#10426](https://github.com/react/react/pull/10426), [#10715](https://github.com/react/react/pull/10715), [#15593](https://github.com/react/react/pull/15593), [#15272](https://github.com/react/react/pull/15272), [#15578](https://github.com/react/react/pull/15578), [#15769](https://github.com/react/react/pull/15769), [#17058](https://github.com/react/react/pull/17058), [#18796](https://github.com/react/react/pull/18796), [#19121](https://github.com/react/react/pull/19121), [#19703](https://github.com/react/react/pull/19703), [#19719](https://github.com/react/react/pull/19719), [#19724](https://github.com/react/react/pull/19724), [#20672](https://github.com/react/react/pull/20672), [#20976](https://github.com/react/react/pull/20976) by [@acdlite](https://github.com/acdlite), [@lunaruan](https://github.com/lunaruan), [@rickhanlonii](https://github.com/rickhanlonii), and [@sebmarkbage](https://github.com/sebmarkbage)) +* Add `useId` for generating unique IDs. ([#17322](https://github.com/react/react/pull/17322), [#18576](https://github.com/react/react/pull/18576), [#22644](https://github.com/react/react/pull/22644), [#22672](https://github.com/react/react/pull/22672), [#21260](https://github.com/react/react/pull/21260) by [@acdlite](https://github.com/acdlite), [@lunaruan](https://github.com/lunaruan), and [@sebmarkbage](https://github.com/sebmarkbage)) +* Add `useSyncExternalStore` to help external store libraries integrate with React. ([#15022](https://github.com/react/react/pull/15022), [#18000](https://github.com/react/react/pull/18000), [#18771](https://github.com/react/react/pull/18771), [#22211](https://github.com/react/react/pull/22211), [#22292](https://github.com/react/react/pull/22292), [#22239](https://github.com/react/react/pull/22239), [#22347](https://github.com/react/react/pull/22347), [#23150](https://github.com/react/react/pull/23150) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), and [@drarmstr](https://github.com/drarmstr)) +* Add `startTransition` as a version of `useTransition` without pending feedback. ([#19696](https://github.com/react/react/pull/19696) by [@rickhanlonii](https://github.com/rickhanlonii)) +* Add `useInsertionEffect` for CSS-in-JS libraries. ([#21913](https://github.com/react/react/pull/21913) by [@rickhanlonii](https://github.com/rickhanlonii)) +* Make Suspense remount layout effects when content reappears. ([#19322](https://github.com/react/react/pull/19322), [#19374](https://github.com/react/react/pull/19374), [#19523](https://github.com/react/react/pull/19523), [#20625](https://github.com/react/react/pull/20625), [#21079](https://github.com/react/react/pull/21079) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), and [@lunaruan](https://github.com/lunaruan)) +* Make `<StrictMode>` re-run effects to check for restorable state. ([#19523](https://github.com/react/react/pull/19523) , [#21418](https://github.com/react/react/pull/21418) by [@bvaughn](https://github.com/bvaughn) and [@lunaruan](https://github.com/lunaruan)) +* Assume Symbols are always available. ([#23348](https://github.com/react/react/pull/23348) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Remove `object-assign` polyfill. ([#23351](https://github.com/react/react/pull/23351) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Remove unsupported `unstable_changedBits` API. ([#20953](https://github.com/react/react/pull/20953) by [@acdlite](https://github.com/acdlite)) +* Allow components to render undefined. ([#21869](https://github.com/react/react/pull/21869) by [@rickhanlonii](https://github.com/rickhanlonii)) +* Flush `useEffect` resulting from discrete events like clicks synchronously. ([#21150](https://github.com/react/react/pull/21150) by [@acdlite](https://github.com/acdlite)) +* Suspense `fallback={undefined}` now behaves the same as `null` and isn't ignored. ([#21854](https://github.com/react/react/pull/21854) by [@rickhanlonii](https://github.com/rickhanlonii)) +* Consider all `lazy()` resolving to the same component equivalent. ([#20357](https://github.com/react/react/pull/20357) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Don't patch console during first render. ([#22308](https://github.com/react/react/pull/22308) by [@lunaruan](https://github.com/lunaruan)) +* Improve memory usage. ([#21039](https://github.com/react/react/pull/21039) by [@bgirard](https://github.com/bgirard)) +* Improve messages if string coercion throws (Temporal.*, Symbol, etc.) ([#22064](https://github.com/react/react/pull/22064) by [@justingrant](https://github.com/justingrant)) +* Use `setImmediate` when available over `MessageChannel`. ([#20834](https://github.com/react/react/pull/20834) by [@gaearon](https://github.com/gaearon)) +* Fix context failing to propagate inside suspended trees. ([#23095](https://github.com/react/react/pull/23095) by [@gaearon](https://github.com/gaearon)) +* Fix `useReducer` observing incorrect props by removing the eager bailout mechanism. ([#22445](https://github.com/react/react/pull/22445) by [@josephsavona](https://github.com/josephsavona)) +* Fix `setState` being ignored in Safari when appending iframes. ([#23111](https://github.com/react/react/pull/23111) by [@gaearon](https://github.com/gaearon)) +* Fix a crash when rendering `ZonedDateTime` in the tree. ([#20617](https://github.com/react/react/pull/20617) by [@dimaqq](https://github.com/dimaqq)) +* Fix a crash when document is set to `null` in tests. ([#22695](https://github.com/react/react/pull/22695) by [@SimenB](https://github.com/SimenB)) +* Fix `onLoad` not triggering when concurrent features are on. ([#23316](https://github.com/react/react/pull/23316) by [@gnoff](https://github.com/gnoff)) +* Fix a warning when a selector returns `NaN`. ([#23333](https://github.com/react/react/pull/23333) by [@hachibeeDI](https://github.com/hachibeeDI)) +* Fix a crash when document is set to `null` in tests. ([#22695](https://github.com/react/react/pull/22695) by [@SimenB](https://github.com/SimenB)) +* Fix the generated license header. ([#23004](https://github.com/react/react/pull/23004) by [@vitaliemiron](https://github.com/vitaliemiron)) +* Add `package.json` as one of the entry points. ([#22954](https://github.com/react/react/pull/22954) by [@Jack](https://github.com/Jack-Works)) +* Allow suspending outside a Suspense boundary. ([#23267](https://github.com/react/react/pull/23267) by [@acdlite](https://github.com/acdlite)) +* Log a recoverable error whenever hydration fails. ([#23319](https://github.com/react/react/pull/23319) by [@acdlite](https://github.com/acdlite)) ### React DOM {/*react-dom*/} -* Add `createRoot` and `hydrateRoot`. ([#10239](https://github.com/facebook/react/pull/10239), [#11225](https://github.com/facebook/react/pull/11225), [#12117](https://github.com/facebook/react/pull/12117), [#13732](https://github.com/facebook/react/pull/13732), [#15502](https://github.com/facebook/react/pull/15502), [#15532](https://github.com/facebook/react/pull/15532), [#17035](https://github.com/facebook/react/pull/17035), [#17165](https://github.com/facebook/react/pull/17165), [#20669](https://github.com/facebook/react/pull/20669), [#20748](https://github.com/facebook/react/pull/20748), [#20888](https://github.com/facebook/react/pull/20888), [#21072](https://github.com/facebook/react/pull/21072), [#21417](https://github.com/facebook/react/pull/21417), [#21652](https://github.com/facebook/react/pull/21652), [#21687](https://github.com/facebook/react/pull/21687), [#23207](https://github.com/facebook/react/pull/23207), [#23385](https://github.com/facebook/react/pull/23385) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), [@gaearon](https://github.com/gaearon), [@lunaruan](https://github.com/lunaruan), [@rickhanlonii](https://github.com/rickhanlonii), [@trueadm](https://github.com/trueadm), and [@sebmarkbage](https://github.com/sebmarkbage)) -* Add selective hydration. ([#14717](https://github.com/facebook/react/pull/14717), [#14884](https://github.com/facebook/react/pull/14884), [#16725](https://github.com/facebook/react/pull/16725), [#16880](https://github.com/facebook/react/pull/16880), [#17004](https://github.com/facebook/react/pull/17004), [#22416](https://github.com/facebook/react/pull/22416), [#22629](https://github.com/facebook/react/pull/22629), [#22448](https://github.com/facebook/react/pull/22448), [#22856](https://github.com/facebook/react/pull/22856), [#23176](https://github.com/facebook/react/pull/23176) by [@acdlite](https://github.com/acdlite), [@gaearon](https://github.com/gaearon), [@salazarm](https://github.com/salazarm), and [@sebmarkbage](https://github.com/sebmarkbage)) -* Add `aria-description` to the list of known ARIA attributes. ([#22142](https://github.com/facebook/react/pull/22142) by [@mahyareb](https://github.com/mahyareb)) -* Add `onResize` event to video elements. ([#21973](https://github.com/facebook/react/pull/21973) by [@rileyjshaw](https://github.com/rileyjshaw)) -* Add `imageSizes` and `imageSrcSet` to known props. ([#22550](https://github.com/facebook/react/pull/22550) by [@eps1lon](https://github.com/eps1lon)) -* Allow non-string `<option>` children if `value` is provided. ([#21431](https://github.com/facebook/react/pull/21431) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Fix `aspectRatio` style not being applied. ([#21100](https://github.com/facebook/react/pull/21100) by [@gaearon](https://github.com/gaearon)) -* Warn if `renderSubtreeIntoContainer` is called. ([#23355](https://github.com/facebook/react/pull/23355) by [@acdlite](https://github.com/acdlite)) +* Add `createRoot` and `hydrateRoot`. ([#10239](https://github.com/react/react/pull/10239), [#11225](https://github.com/react/react/pull/11225), [#12117](https://github.com/react/react/pull/12117), [#13732](https://github.com/react/react/pull/13732), [#15502](https://github.com/react/react/pull/15502), [#15532](https://github.com/react/react/pull/15532), [#17035](https://github.com/react/react/pull/17035), [#17165](https://github.com/react/react/pull/17165), [#20669](https://github.com/react/react/pull/20669), [#20748](https://github.com/react/react/pull/20748), [#20888](https://github.com/react/react/pull/20888), [#21072](https://github.com/react/react/pull/21072), [#21417](https://github.com/react/react/pull/21417), [#21652](https://github.com/react/react/pull/21652), [#21687](https://github.com/react/react/pull/21687), [#23207](https://github.com/react/react/pull/23207), [#23385](https://github.com/react/react/pull/23385) by [@acdlite](https://github.com/acdlite), [@bvaughn](https://github.com/bvaughn), [@gaearon](https://github.com/gaearon), [@lunaruan](https://github.com/lunaruan), [@rickhanlonii](https://github.com/rickhanlonii), [@trueadm](https://github.com/trueadm), and [@sebmarkbage](https://github.com/sebmarkbage)) +* Add selective hydration. ([#14717](https://github.com/react/react/pull/14717), [#14884](https://github.com/react/react/pull/14884), [#16725](https://github.com/react/react/pull/16725), [#16880](https://github.com/react/react/pull/16880), [#17004](https://github.com/react/react/pull/17004), [#22416](https://github.com/react/react/pull/22416), [#22629](https://github.com/react/react/pull/22629), [#22448](https://github.com/react/react/pull/22448), [#22856](https://github.com/react/react/pull/22856), [#23176](https://github.com/react/react/pull/23176) by [@acdlite](https://github.com/acdlite), [@gaearon](https://github.com/gaearon), [@salazarm](https://github.com/salazarm), and [@sebmarkbage](https://github.com/sebmarkbage)) +* Add `aria-description` to the list of known ARIA attributes. ([#22142](https://github.com/react/react/pull/22142) by [@mahyareb](https://github.com/mahyareb)) +* Add `onResize` event to video elements. ([#21973](https://github.com/react/react/pull/21973) by [@rileyjshaw](https://github.com/rileyjshaw)) +* Add `imageSizes` and `imageSrcSet` to known props. ([#22550](https://github.com/react/react/pull/22550) by [@eps1lon](https://github.com/eps1lon)) +* Allow non-string `<option>` children if `value` is provided. ([#21431](https://github.com/react/react/pull/21431) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Fix `aspectRatio` style not being applied. ([#21100](https://github.com/react/react/pull/21100) by [@gaearon](https://github.com/gaearon)) +* Warn if `renderSubtreeIntoContainer` is called. ([#23355](https://github.com/react/react/pull/23355) by [@acdlite](https://github.com/acdlite)) ### React DOM Server {/*react-dom-server-1*/} -* Add the new streaming renderer. ([#14144](https://github.com/facebook/react/pull/14144), [#20970](https://github.com/facebook/react/pull/20970), [#21056](https://github.com/facebook/react/pull/21056), [#21255](https://github.com/facebook/react/pull/21255), [#21200](https://github.com/facebook/react/pull/21200), [#21257](https://github.com/facebook/react/pull/21257), [#21276](https://github.com/facebook/react/pull/21276), [#22443](https://github.com/facebook/react/pull/22443), [#22450](https://github.com/facebook/react/pull/22450), [#23247](https://github.com/facebook/react/pull/23247), [#24025](https://github.com/facebook/react/pull/24025), [#24030](https://github.com/facebook/react/pull/24030) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Fix context providers in SSR when handling multiple requests. ([#23171](https://github.com/facebook/react/pull/23171) by [@frandiox](https://github.com/frandiox)) -* Revert to client render on text mismatch. ([#23354](https://github.com/facebook/react/pull/23354) by [@acdlite](https://github.com/acdlite)) -* Deprecate `renderToNodeStream`. ([#23359](https://github.com/facebook/react/pull/23359) by [@sebmarkbage](https://github.com/sebmarkbage)) -* Fix a spurious error log in the new server renderer. ([#24043](https://github.com/facebook/react/pull/24043) by [@eps1lon](https://github.com/eps1lon)) -* Fix a bug in the new server renderer. ([#22617](https://github.com/facebook/react/pull/22617) by [@shuding](https://github.com/shuding)) -* Ignore function and symbol values inside custom elements on the server. ([#21157](https://github.com/facebook/react/pull/21157) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Add the new streaming renderer. ([#14144](https://github.com/react/react/pull/14144), [#20970](https://github.com/react/react/pull/20970), [#21056](https://github.com/react/react/pull/21056), [#21255](https://github.com/react/react/pull/21255), [#21200](https://github.com/react/react/pull/21200), [#21257](https://github.com/react/react/pull/21257), [#21276](https://github.com/react/react/pull/21276), [#22443](https://github.com/react/react/pull/22443), [#22450](https://github.com/react/react/pull/22450), [#23247](https://github.com/react/react/pull/23247), [#24025](https://github.com/react/react/pull/24025), [#24030](https://github.com/react/react/pull/24030) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Fix context providers in SSR when handling multiple requests. ([#23171](https://github.com/react/react/pull/23171) by [@frandiox](https://github.com/frandiox)) +* Revert to client render on text mismatch. ([#23354](https://github.com/react/react/pull/23354) by [@acdlite](https://github.com/acdlite)) +* Deprecate `renderToNodeStream`. ([#23359](https://github.com/react/react/pull/23359) by [@sebmarkbage](https://github.com/sebmarkbage)) +* Fix a spurious error log in the new server renderer. ([#24043](https://github.com/react/react/pull/24043) by [@eps1lon](https://github.com/eps1lon)) +* Fix a bug in the new server renderer. ([#22617](https://github.com/react/react/pull/22617) by [@shuding](https://github.com/shuding)) +* Ignore function and symbol values inside custom elements on the server. ([#21157](https://github.com/react/react/pull/21157) by [@sebmarkbage](https://github.com/sebmarkbage)) ### React DOM Test Utils {/*react-dom-test-utils*/} -* Throw when `act` is used in production. ([#21686](https://github.com/facebook/react/pull/21686) by [@acdlite](https://github.com/acdlite)) -* Support disabling spurious act warnings with `global.IS_REACT_ACT_ENVIRONMENT`. ([#22561](https://github.com/facebook/react/pull/22561) by [@acdlite](https://github.com/acdlite)) -* Expand act warning to cover all APIs that might schedule React work. ([#22607](https://github.com/facebook/react/pull/22607) by [@acdlite](https://github.com/acdlite)) -* Make `act` batch updates. ([#21797](https://github.com/facebook/react/pull/21797) by [@acdlite](https://github.com/acdlite)) -* Remove warning for dangling passive effects. ([#22609](https://github.com/facebook/react/pull/22609) by [@acdlite](https://github.com/acdlite)) +* Throw when `act` is used in production. ([#21686](https://github.com/react/react/pull/21686) by [@acdlite](https://github.com/acdlite)) +* Support disabling spurious act warnings with `global.IS_REACT_ACT_ENVIRONMENT`. ([#22561](https://github.com/react/react/pull/22561) by [@acdlite](https://github.com/acdlite)) +* Expand act warning to cover all APIs that might schedule React work. ([#22607](https://github.com/react/react/pull/22607) by [@acdlite](https://github.com/acdlite)) +* Make `act` batch updates. ([#21797](https://github.com/react/react/pull/21797) by [@acdlite](https://github.com/acdlite)) +* Remove warning for dangling passive effects. ([#22609](https://github.com/react/react/pull/22609) by [@acdlite](https://github.com/acdlite)) ### React Refresh {/*react-refresh*/} -* Track late-mounted roots in Fast Refresh. ([#22740](https://github.com/facebook/react/pull/22740) by [@anc95](https://github.com/anc95)) -* Add `exports` field to `package.json`. ([#23087](https://github.com/facebook/react/pull/23087) by [@otakustay](https://github.com/otakustay)) +* Track late-mounted roots in Fast Refresh. ([#22740](https://github.com/react/react/pull/22740) by [@anc95](https://github.com/anc95)) +* Add `exports` field to `package.json`. ([#23087](https://github.com/react/react/pull/23087) by [@otakustay](https://github.com/otakustay)) ### Server Components (Experimental) {/*server-components-experimental*/} -* Add Server Context support. ([#23244](https://github.com/facebook/react/pull/23244) by [@salazarm](https://github.com/salazarm)) -* Add `lazy` support. ([#24068](https://github.com/facebook/react/pull/24068) by [@gnoff](https://github.com/gnoff)) -* Update webpack plugin for webpack 5 ([#22739](https://github.com/facebook/react/pull/22739) by [@michenly](https://github.com/michenly)) -* Fix a mistake in the Node loader. ([#22537](https://github.com/facebook/react/pull/22537) by [@btea](https://github.com/btea)) -* Use `globalThis` instead of `window` for edge environments. ([#22777](https://github.com/facebook/react/pull/22777) by [@huozhi](https://github.com/huozhi)) +* Add Server Context support. ([#23244](https://github.com/react/react/pull/23244) by [@salazarm](https://github.com/salazarm)) +* Add `lazy` support. ([#24068](https://github.com/react/react/pull/24068) by [@gnoff](https://github.com/gnoff)) +* Update webpack plugin for webpack 5 ([#22739](https://github.com/react/react/pull/22739) by [@michenly](https://github.com/michenly)) +* Fix a mistake in the Node loader. ([#22537](https://github.com/react/react/pull/22537) by [@btea](https://github.com/btea)) +* Use `globalThis` instead of `window` for edge environments. ([#22777](https://github.com/react/react/pull/22777) by [@huozhi](https://github.com/huozhi)) diff --git a/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md b/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md index 5e8456ea3..e5c18d9d2 100644 --- a/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md +++ b/src/content/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022.md @@ -66,7 +66,7 @@ Currently, React has two profiling tools. The [original Profiler](https://legacy We’ve realized that developers don’t find knowing about individual slow commits or components out of context that useful. It’s more useful to know about what actually causes the slow commits. And that developers want to be able to track specific interactions (eg a button click, an initial load, or a page navigation) to watch for performance regressions and to understand why an interaction was slow and how to fix it. -We previously tried to solve this issue by creating an [Interaction Tracing API](https://gist.github.com/bvaughn/8de925562903afd2e7a12554adcdda16), but it had some fundamental design flaws that reduced the accuracy of tracking why an interaction was slow and sometimes resulted in interactions never ending. We ended up [removing this API](https://github.com/facebook/react/pull/20037) because of these issues. +We previously tried to solve this issue by creating an [Interaction Tracing API](https://gist.github.com/bvaughn/8de925562903afd2e7a12554adcdda16), but it had some fundamental design flaws that reduced the accuracy of tracking why an interaction was slow and sometimes resulted in interactions never ending. We ended up [removing this API](https://github.com/react/react/pull/20037) because of these issues. We are working on a new version for the Interaction Tracing API (tentatively called Transition Tracing because it is initiated via `startTransition`) that solves these problems. diff --git a/src/content/blog/2024/04/25/react-19-upgrade-guide.md b/src/content/blog/2024/04/25/react-19-upgrade-guide.md index 1823ebdfb..6f918a2a9 100644 --- a/src/content/blog/2024/04/25/react-19-upgrade-guide.md +++ b/src/content/blog/2024/04/25/react-19-upgrade-guide.md @@ -24,7 +24,7 @@ To help make the upgrade to React 19 easier, we've published a `react@18.3` rele We recommend upgrading to React 18.3 first to help identify any issues before upgrading to React 19. -For a list of changes in 18.3 see the [Release Notes](https://github.com/facebook/react/blob/main/CHANGELOG.md#1830-april-25-2024). +For a list of changes in 18.3 see the [Release Notes](https://github.com/react/react/blob/main/CHANGELOG.md#1830-april-25-2024). </Note> @@ -38,7 +38,7 @@ In this post, we will guide you through the steps for upgrading to React 19: - [TypeScript changes](#typescript-changes) - [Changelog](#changelog) -If you'd like to help us test React 19, follow the steps in this upgrade guide and [report any issues](https://github.com/facebook/react/issues/new?assignees=&labels=React+19&projects=&template=19.md&title=%5BReact+19%5D) you encounter. For a list of new features added to React 19, see the [React 19 release post](/blog/2024/12/05/react-19). +If you'd like to help us test React 19, follow the steps in this upgrade guide and [report any issues](https://github.com/react/react/issues/new?assignees=&labels=React+19&projects=&template=19.md&title=%5BReact+19%5D) you encounter. For a list of new features added to React 19, see the [React 19 release post](/blog/2024/12/05/react-19). --- ## Installing {/*installing*/} @@ -256,7 +256,7 @@ class Child extends React.Component { #### Removed: string refs {/*removed-string-refs*/} String refs were deprecated in [March, 2018 (v16.3.0)](https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html). -Class components supported string refs before being replaced by ref callbacks due to [multiple downsides](https://github.com/facebook/react/issues/1373). In React 19, we're removing string refs to make React simpler and easier to understand. +Class components supported string refs before being replaced by ref callbacks due to [multiple downsides](https://github.com/react/react/issues/1373). In React 19, we're removing string refs to make React simpler and easier to understand. If you're still using string refs in class components, you'll need to migrate to ref callbacks: @@ -730,24 +730,24 @@ const reducer = (state: State, action: Action) => state; ### Other breaking changes {/*other-breaking-changes*/} -- **react-dom**: Error for javascript URLs in `src` and `href` [#26507](https://github.com/facebook/react/pull/26507) -- **react-dom**: Remove `errorInfo.digest` from `onRecoverableError` [#28222](https://github.com/facebook/react/pull/28222) -- **react-dom**: Remove `unstable_flushControlled` [#26397](https://github.com/facebook/react/pull/26397) -- **react-dom**: Remove `unstable_createEventHandle` [#28271](https://github.com/facebook/react/pull/28271) -- **react-dom**: Remove `unstable_renderSubtreeIntoContainer` [#28271](https://github.com/facebook/react/pull/28271) -- **react-dom**: Remove `unstable_runWithPriority` [#28271](https://github.com/facebook/react/pull/28271) -- **react-is**: Remove deprecated methods from `react-is` [28224](https://github.com/facebook/react/pull/28224) +- **react-dom**: Error for javascript URLs in `src` and `href` [#26507](https://github.com/react/react/pull/26507) +- **react-dom**: Remove `errorInfo.digest` from `onRecoverableError` [#28222](https://github.com/react/react/pull/28222) +- **react-dom**: Remove `unstable_flushControlled` [#26397](https://github.com/react/react/pull/26397) +- **react-dom**: Remove `unstable_createEventHandle` [#28271](https://github.com/react/react/pull/28271) +- **react-dom**: Remove `unstable_renderSubtreeIntoContainer` [#28271](https://github.com/react/react/pull/28271) +- **react-dom**: Remove `unstable_runWithPriority` [#28271](https://github.com/react/react/pull/28271) +- **react-is**: Remove deprecated methods from `react-is` [28224](https://github.com/react/react/pull/28224) ### Other notable changes {/*other-notable-changes*/} -- **react**: Batch sync, default and continuous lanes [#25700](https://github.com/facebook/react/pull/25700) -- **react**: Don't prerender siblings of suspended component [#26380](https://github.com/facebook/react/pull/26380) -- **react**: Detect infinite update loops caused by render phase updates [#26625](https://github.com/facebook/react/pull/26625) -- **react-dom**: Transitions in popstate are now synchronous [#26025](https://github.com/facebook/react/pull/26025) -- **react-dom**: Remove layout effect warning during SSR [#26395](https://github.com/facebook/react/pull/26395) -- **react-dom**: Warn and don’t set empty string for src/href (except anchor tags) [#28124](https://github.com/facebook/react/pull/28124) +- **react**: Batch sync, default and continuous lanes [#25700](https://github.com/react/react/pull/25700) +- **react**: Don't prerender siblings of suspended component [#26380](https://github.com/react/react/pull/26380) +- **react**: Detect infinite update loops caused by render phase updates [#26625](https://github.com/react/react/pull/26625) +- **react-dom**: Transitions in popstate are now synchronous [#26025](https://github.com/react/react/pull/26025) +- **react-dom**: Remove layout effect warning during SSR [#26395](https://github.com/react/react/pull/26395) +- **react-dom**: Warn and don’t set empty string for src/href (except anchor tags) [#28124](https://github.com/react/react/pull/28124) -For a full list of changes, please see the [Changelog](https://github.com/facebook/react/blob/main/CHANGELOG.md#1900-december-5-2024). +For a full list of changes, please see the [Changelog](https://github.com/react/react/blob/main/CHANGELOG.md#1900-december-5-2024). --- diff --git a/src/content/blog/2024/05/22/react-conf-2024-recap.md b/src/content/blog/2024/05/22/react-conf-2024-recap.md new file mode 100644 index 000000000..d0774782a --- /dev/null +++ b/src/content/blog/2024/05/22/react-conf-2024-recap.md @@ -0,0 +1,124 @@ +--- +title: "React Conf 2024 Recap" +author: Ricky Hanlon +date: 2024/05/22 +description: Last week we hosted React Conf 2024, a two-day conference in Henderson, Nevada where 700+ attendees gathered in-person to discuss the latest in UI engineering. In this post, we'll summarize the talks and announcements from the event. +--- + +May 22, 2024 by [Ricky Hanlon](https://twitter.com/rickhanlonii). + +--- + +<Intro> + +Last week we hosted React Conf 2024, a two-day conference in Henderson, Nevada where 700+ attendees gathered in-person to discuss the latest in UI engineering. This was our first in-person conference since 2019, and we were thrilled to be able to bring the community together again. + +</Intro> + +--- + +At React Conf 2024, we announced the [React 19 RC](/blog/2024/12/05/react-19), the [React Native New Architecture Beta](https://github.com/reactwg/react-native-new-architecture/discussions/189), and an experimental release of the [React Compiler](/learn/react-compiler). The community also took the stage to announce [React Router v7](https://remix.run/blog/merging-remix-and-react-router), [Universal Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=20765s) in Expo Router, React Server Components in [RedwoodJS](https://redwoodjs.com/blog/rsc-now-in-redwoodjs), and much more. + +The entire [day 1](https://www.youtube.com/watch?v=T8TZQ6k4SLE) and [day 2](https://www.youtube.com/watch?v=0ckOUBiuxVY) streams are available online. In this post, we'll summarize the talks and announcements from the event. + +## Day 1 {/*day-1*/} + +_[Watch the full day 1 stream here.](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=973s)_ + +To kick off day 1, Meta CTO [Andrew "Boz" Bosworth](https://www.threads.net/@boztank) shared a welcome message followed by an introduction by [Seth Webster](https://twitter.com/sethwebster), who manages the React Org at Meta, and our MC [Ashley Narcisse](https://twitter.com/_darkfadr). + +In the day 1 keynote, [Joe Savona](https://twitter.com/en_JS) shared our goals and vision for React to make it easy for anyone to build great user experiences. [Lauren Tan](https://twitter.com/potetotes) followed with a State of React, where she shared that React was downloaded over 1 billion times in 2023, and that 37% of new developers learn to program with React. Finally, she highlighted the work of the React community to make React, React. + +For more, check out these talks from the community later in the conference: + +- [Vanilla React](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=5542s) by [Ryan Florence](https://twitter.com/ryanflorence) +- [React Rhythm & Blues](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=12728s) by [Lee Robinson](https://twitter.com/leeerob) +- [RedwoodJS, now with React Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=26815s) by [Amy Dutton](https://twitter.com/selfteachme) +- [Introducing Universal React Server Components in Expo Router](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=20765s) by [Evan Bacon](https://twitter.com/Baconbrix) + +Next in the keynote, [Josh Story](https://twitter.com/joshcstory) and [Andrew Clark](https://twitter.com/acdlite) shared new features coming in React 19, and announced the React 19 RC which is ready for testing in production. Check out all the features in the [React 19 release post](/blog/2024/12/05/react-19), and see these talks for deep dives on the new features: + +- [What's new in React 19](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=8880s) by [Lydia Hallie](https://twitter.com/lydiahallie) +- [React Unpacked: A Roadmap to React 19](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=10112s) by [Sam Selikoff](https://twitter.com/samselikoff) +- [React 19 Deep Dive: Coordinating HTML](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=24916s) by [Josh Story](https://twitter.com/joshcstory) +- [Enhancing Forms with React Server Components](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=25280s) by [Aurora Walberg Scharff](https://twitter.com/aurorascharff) +- [React for Two Computers](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=18825s) by [Dan Abramov](https://bsky.app/profile/danabra.mov) +- [And Now You Understand React Server Components](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=11256s) by [Kent C. Dodds](https://twitter.com/kentcdodds) + +Finally, we ended the keynote with [Joe Savona](https://twitter.com/en_JS), [Sathya Gunasekaran](https://twitter.com/_gsathya), and [Mofei Zhang](https://twitter.com/zmofei) announcing that the React Compiler is now [Open Source](https://github.com/react/react/pull/29061), and sharing an experimental version of the React Compiler to try out. + +For more information on using the Compiler and how it works, check out [the docs](/learn/react-compiler) and these talks: + +- [Forget About Memo](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=12020s) by [Lauren Tan](https://twitter.com/potetotes) +- [React Compiler Deep Dive](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=9313s) by [Sathya Gunasekaran](https://twitter.com/_gsathya) and [Mofei Zhang](https://twitter.com/zmofei) + +Watch the full day 1 keynote here: + +<YouTubeIframe src="https://www.youtube.com/embed/T8TZQ6k4SLE?t=973s" /> + +## Day 2 {/*day-2*/} + +_[Watch the full day 2 stream here.](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=1720s)_ + +To kick off day 2, [Seth Webster](https://twitter.com/sethwebster) shared a welcome message, followed by a Thank You from [Eli White](https://x.com/Eli_White) and an introduction by our Chief Vibes Officer [Ashley Narcisse](https://twitter.com/_darkfadr). + +In the day 2 keynote, [Nicola Corti](https://twitter.com/cortinico) shared the State of React Native, including 78 million downloads in 2023. He also highlighted apps using React Native including 2000+ screens used inside of Meta; the product details page in Facebook Marketplace, which is visited more than 2 billion times per day; and part of the Microsoft Windows Start Menu and some features in almost every Microsoft Office product across mobile and desktop. + +Nicola also highlighted all the work the community does to support React Native including libraries, frameworks, and multiple platforms. For more, check out these talks from the community: + +- [Extending React Native beyond Mobile and Desktop Apps](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=5798s) by [Chris Traganos](https://twitter.com/chris_trag) and [Anisha Malde](https://twitter.com/anisha_malde) +- [Spatial computing with React](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=22525s) by [Michał Pierzchała](https://twitter.com/thymikee) + +[Riccardo Cipolleschi](https://twitter.com/cipolleschir) continued the day 2 keynote by announcing that the React Native New Architecture is now in Beta and ready for apps to adopt in production. He shared new features and improvements in the new architecture, and shared the roadmap for the future of React Native. For more check out: + +- [Cross Platform React](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=26569s) by [Olga Zinoveva](https://github.com/SlyCaptainFlint) and [Naman Goel](https://twitter.com/naman34) + +Next in the keynote, Nicola announced that we are now recommending starting with a framework like Expo for all new apps created with React Native. With the change, he also announced a new React Native homepage and new Getting Started docs. You can view the new Getting Started guide in the [React Native docs](https://reactnative.dev/docs/next/environment-setup). + +Finally, to end the keynote, [Kadi Kraman](https://twitter.com/kadikraman) shared the latest features and improvements in Expo, and how to get started developing with React Native using Expo. + +Watch the full day 2 keynote here: + +<YouTubeIframe src="https://www.youtube.com/embed/0ckOUBiuxVY?t=1720s" /> + +## Q&A {/*q-and-a*/} + +The React and React Native teams also ended each day with a Q&A session: + +- [React Q&A](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=27518s) hosted by [Michael Chan](https://twitter.com/chantastic) +- [React Native Q&A](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=27935s) hosted by [Jamon Holmgren](https://twitter.com/jamonholmgren) + +## And more... {/*and-more*/} + +We also heard talks on accessibility, error reporting, css, and more: + +- [Demystifying accessibility in React apps](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=20655s) by [Kateryna Porshnieva](https://twitter.com/krambertech) +- [Pigment CSS, CSS in the server component age](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=21696s) by [Olivier Tassinari](https://twitter.com/olivtassinari) +- [Real-time React Server Components](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=24070s) by [Sunil Pai](https://twitter.com/threepointone) +- [Let's break React Rules](https://www.youtube.com/watch?v=T8TZQ6k4SLE&t=25862s) by [Charlotte Isambert](https://twitter.com/c_isambert) +- [Solve 100% of your errors](https://www.youtube.com/watch?v=0ckOUBiuxVY&t=19881s) by [Ryan Albrecht](https://github.com/ryan953) + +## Thank you {/*thank-you*/} + +Thank you to all the staff, speakers, and participants who made React Conf 2024 possible. There are too many to list, but we want to thank a few in particular. + +Thank you to [Barbara Markiewicz](https://twitter.com/barbara_markie), the team at [Callstack](https://www.callstack.com/), and our React Team Developer Advocate [Matt Carroll](https://twitter.com/mattcarrollcode) for helping to plan the entire event; and to [Sunny Leggett](https://zeroslopeevents.com/about) and everyone from [Zero Slope](https://zeroslopeevents.com) for helping to organize the event. + +Thank you [Ashley Narcisse](https://twitter.com/_darkfadr) for being our MC and Chief Vibes Officer; and to [Michael Chan](https://twitter.com/chantastic) and [Jamon Holmgren](https://twitter.com/jamonholmgren) for hosting the Q&A sessions. + +Thank you [Seth Webster](https://twitter.com/sethwebster) and [Eli White](https://x.com/Eli_White) for welcoming us each day and providing direction on structure and content; and to [Tom Occhino](https://twitter.com/tomocchino) for joining us with a special message during the after-party. + +Thank you [Ricky Hanlon](https://www.youtube.com/watch?v=FxTZL2U-uKg&t=1263s) for providing detailed feedback on talks, working on slide designs, and generally filling in the gaps to sweat the details. + +Thank you [Callstack](https://www.callstack.com/) for building the conference website; and to [Kadi Kraman](https://twitter.com/kadikraman) and the [Expo](https://expo.dev/) team for building the conference mobile app. + +Thank you to all the sponsors who made the event possible: [Remix](https://remix.run/), [Amazon](https://developer.amazon.com/apps-and-games?cmp=US_2024_05_3P_React-Conf-2024&ch=prtnr&chlast=prtnr&pub=ref&publast=ref&type=org&typelast=org), [MUI](https://mui.com/), [Sentry](https://sentry.io/for/react/?utm_source=sponsored-conf&utm_medium=sponsored-event&utm_campaign=frontend-fy25q2-evergreen&utm_content=logo-reactconf2024-learnmore), [Abbott](https://www.jobs.abbott/software), [Expo](https://expo.dev/), [RedwoodJS](https://rwsdk.com/), and [Vercel](https://vercel.com). + +Thank you to the AV Team for the visuals, stage, and sound; and to the Westin Hotel for hosting us. + +Thank you to all the speakers who shared their knowledge and experiences with the community. + +Finally, thank you to everyone who attended in person and online to show what makes React, React. React is more than a library, it is a community, and it was inspiring to see everyone come together to share and learn together. + +See you next time! + diff --git a/src/content/blog/2024/10/21/react-compiler-beta-release.md b/src/content/blog/2024/10/21/react-compiler-beta-release.md new file mode 100644 index 000000000..5cc5f19ae --- /dev/null +++ b/src/content/blog/2024/10/21/react-compiler-beta-release.md @@ -0,0 +1,134 @@ +--- +title: "React Compiler Beta Release" +author: Lauren Tan +date: 2024/10/21 +description: At React Conf 2024, we announced the experimental release of React Compiler, a build-time tool that optimizes your React app through automatic memoization. In this post, we want to share what's next for open source, and our progress on the compiler. + +--- + +October 21, 2024 by [Lauren Tan](https://twitter.com/potetotes). + +--- + +<Note> + +### React Compiler is now stable! {/*react-compiler-is-now-in-rc*/} + +Please see the [stable release blog post](/blog/2025/10/07/react-compiler-1) for details. + +</Note> + +<Intro> + +The React team is excited to share new updates: + +</Intro> + +1. We're publishing React Compiler Beta today, so that early adopters and library maintainers can try it and provide feedback. +2. We're officially supporting React Compiler for apps on React 17+, through an optional `react-compiler-runtime` package. +3. We're opening up public membership of the [React Compiler Working Group](https://github.com/reactwg/react-compiler) to prepare the community for gradual adoption of the compiler. + +--- + +At [React Conf 2024](/blog/2024/05/22/react-conf-2024-recap), we announced the experimental release of React Compiler, a build-time tool that optimizes your React app through automatic memoization. [You can find an introduction to React Compiler here](/learn/react-compiler). + +Since the first release, we've fixed numerous bugs reported by the React community, received several high quality bug fixes and contributions[^1] to the compiler, made the compiler more resilient to the broad diversity of JavaScript patterns, and have continued to roll out the compiler more widely at Meta. + +In this post, we want to share what's next for React Compiler. + +## Try React Compiler Beta today {/*try-react-compiler-beta-today*/} + +At [React India 2024](https://www.youtube.com/watch?v=qd5yk2gxbtg), we shared an update on React Compiler. Today, we are excited to announce a new Beta release of React Compiler and ESLint plugin. New betas are published to npm using the `@beta` tag. + +To install React Compiler Beta: + +<TerminalBlock> +npm install -D babel-plugin-react-compiler@beta eslint-plugin-react-compiler@beta +</TerminalBlock> + +Or, if you're using Yarn: + +<TerminalBlock> +yarn add -D babel-plugin-react-compiler@beta eslint-plugin-react-compiler@beta +</TerminalBlock> + +You can watch [Sathya Gunasekaran's](https://twitter.com/_gsathya) talk at React India here: + +<YouTubeIframe src="https://www.youtube.com/embed/qd5yk2gxbtg" /> + +## We recommend everyone use the React Compiler linter today {/*we-recommend-everyone-use-the-react-compiler-linter-today*/} + +React Compiler’s ESLint plugin helps developers proactively identify and correct [Rules of React](/reference/rules) violations. **We strongly recommend everyone use the linter today**. The linter does not require that you have the compiler installed, so you can use it independently, even if you are not ready to try out the compiler. + +To install the linter only: + +<TerminalBlock> +npm install -D eslint-plugin-react-compiler@beta +</TerminalBlock> + +Or, if you're using Yarn: + +<TerminalBlock> +yarn add -D eslint-plugin-react-compiler@beta +</TerminalBlock> + +After installation you can enable the linter by [adding it to your ESLint config](/learn/react-compiler/installation#eslint-integration). Using the linter helps identify Rules of React breakages, making it easier to adopt the compiler when it's fully released. + +## Backwards Compatibility {/*backwards-compatibility*/} + +React Compiler produces code that depends on runtime APIs added in React 19, but we've since added support for the compiler to also work with React 17 and 18. If you are not on React 19 yet, in the Beta release you can now try out React Compiler by specifying a minimum `target` in your compiler config, and adding `react-compiler-runtime` as a dependency. [You can find docs on this here](/reference/react-compiler/configuration#react-17-18). + +## Using React Compiler in libraries {/*using-react-compiler-in-libraries*/} + +Our initial release was focused on identifying major issues with using the compiler in applications. We've gotten great feedback and have substantially improved the compiler since then. We're now ready for broad feedback from the community, and for library authors to try out the compiler to improve performance and the developer experience of maintaining your library. + +React Compiler can also be used to compile libraries. Because React Compiler needs to run on the original source code prior to any code transformations, it is not possible for an application's build pipeline to compile the libraries they use. Hence, our recommendation is for library maintainers to independently compile and test their libraries with the compiler, and ship compiled code to npm. + +Because your code is pre-compiled, users of your library will not need to have the compiler enabled in order to benefit from the automatic memoization applied to your library. If your library targets apps not yet on React 19, specify a minimum `target` and add `react-compiler-runtime` as a direct dependency. The runtime package will use the correct implementation of APIs depending on the application's version, and polyfill the missing APIs if necessary. + +[You can find more docs on this here.](/reference/react-compiler/compiling-libraries) + +## Opening up React Compiler Working Group to everyone {/*opening-up-react-compiler-working-group-to-everyone*/} + +We previously announced the invite-only [React Compiler Working Group](https://github.com/reactwg/react-compiler) at React Conf to provide feedback, ask questions, and collaborate on the compiler's experimental release. + +From today, together with the Beta release of React Compiler, we are opening up Working Group membership to everyone. The goal of the React Compiler Working Group is to prepare the ecosystem for a smooth, gradual adoption of React Compiler by existing applications and libraries. Please continue to file bug reports in the [React repo](https://github.com/react/react), but please leave feedback, ask questions, or share ideas in the [Working Group discussion forum](https://github.com/reactwg/react-compiler/discussions). + +The core team will also use the discussions repo to share our research findings. As the Stable Release gets closer, any important information will also be posted on this forum. + +## React Compiler at Meta {/*react-compiler-at-meta*/} + +At [React Conf](/blog/2024/05/22/react-conf-2024-recap), we shared that our rollout of the compiler on Quest Store and Instagram were successful. Since then, we've deployed React Compiler across several more major web apps at Meta, including [Facebook](https://www.facebook.com) and [Threads](https://www.threads.net). That means if you've used any of these apps recently, you may have had your experience powered by the compiler. We were able to onboard these apps onto the compiler with few code changes required, in a monorepo with more than 100,000 React components. + +We've seen notable performance improvements across all of these apps. As we've rolled out, we're continuing to see results on the order of [the wins we shared previously at ReactConf](https://youtu.be/lyEKhv8-3n0?t=3223). These apps have already been heavily hand tuned and optimized by Meta engineers and React experts over the years, so even improvements on the order of a few percent are a huge win for us. + +We also expected developer productivity wins from React Compiler. To measure this, we collaborated with our data science partners at Meta[^2] to conduct a thorough statistical analysis of the impact of manual memoization on productivity. Before rolling out the compiler at Meta, we discovered that only about 8% of React pull requests used manual memoization and that these pull requests took 31-46% longer to author[^3]. This confirmed our intuition that manual memoization introduces cognitive overhead, and we anticipate that React Compiler will lead to more efficient code authoring and review. Notably, React Compiler also ensures that *all* code is memoized by default, not just the (in our case) 8% where developers explicitly apply memoization. + +## Roadmap to Stable {/*roadmap-to-stable*/} + +*This is not a final roadmap, and is subject to change.* + +We intend to ship a Release Candidate of the compiler in the near future following the Beta release, when the majority of apps and libraries that follow the Rules of React have been proven to work well with the compiler. After a period of final feedback from the community, we plan on a Stable Release for the compiler. The Stable Release will mark the beginning of a new foundation for React, and all apps and libraries will be strongly recommended to use the compiler and ESLint plugin. + +* ✅ Experimental: Released at React Conf 2024, primarily for feedback from early adopters. +* ✅ Public Beta: Available today, for feedback from the wider community. +* 🚧 Release Candidate (RC): React Compiler works for the majority of rule-following apps and libraries without issue. +* 🚧 General Availability: After final feedback period from the community. + +These releases also include the compiler's ESLint plugin, which surfaces diagnostics statically analyzed by the compiler. We plan to combine the existing eslint-plugin-react-hooks plugin with the compiler's ESLint plugin, so only one plugin needs to be installed. + +Post-Stable, we plan to add more compiler optimizations and improvements. This includes both continual improvements to automatic memoization, and new optimizations altogether, with minimal to no change of product code. Upgrading to each new release of the compiler is aimed to be straightforward, and each upgrade will continue to improve performance and add better handling of diverse JavaScript and React patterns. + +Throughout this process, we also plan to prototype an IDE extension for React. It is still very early in research, so we expect to be able to share more of our findings with you in a future React Labs blog post. + +--- + +Thanks to [Sathya Gunasekaran](https://twitter.com/_gsathya), [Joe Savona](https://twitter.com/en_JS), [Ricky Hanlon](https://twitter.com/rickhanlonii), [Alex Taylor](https://github.com/alexmckenley), [Jason Bonta](https://twitter.com/someextent), and [Eli White](https://twitter.com/Eli_White) for reviewing and editing this post. + +--- + +[^1]: Thanks [@nikeee](https://github.com/react/react/pulls?q=is%3Apr+author%3Anikeee), [@henryqdineen](https://github.com/react/react/pulls?q=is%3Apr+author%3Ahenryqdineen), [@TrickyPi](https://github.com/react/react/pulls?q=is%3Apr+author%3ATrickyPi), and several others for their contributions to the compiler. + +[^2]: Thanks [Vaishali Garg](https://www.linkedin.com/in/vaishaligarg09) for leading this study on React Compiler at Meta, and for reviewing this post. + +[^3]: After controlling on author tenure, diff length/complexity, and other potential confounding factors. \ No newline at end of file diff --git a/src/content/blog/2024/12/05/react-19.md b/src/content/blog/2024/12/05/react-19.md index 749646458..93ac0c360 100644 --- a/src/content/blog/2024/12/05/react-19.md +++ b/src/content/blog/2024/12/05/react-19.md @@ -182,7 +182,7 @@ const [error, submitAction, isPending] = useActionState( `React.useActionState` was previously called `ReactDOM.useFormState` in the Canary releases, but we've renamed it and deprecated `useFormState`. -See [#28491](https://github.com/facebook/react/pull/28491) for more info. +See [#28491](https://github.com/react/react/pull/28491) for more info. </Note> diff --git a/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md b/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md new file mode 100644 index 000000000..dbd673a29 --- /dev/null +++ b/src/content/blog/2025/04/23/react-labs-view-transitions-activity-and-more.md @@ -0,0 +1,14365 @@ +--- +title: "React Labs: View Transitions, Activity, and more" +author: Ricky Hanlon +date: 2025/04/23 +description: In React Labs posts, we write about projects in active research and development. In this post, we're sharing two new experimental features that are ready to try today, and updates on other areas we're working on now. +--- + +April 23, 2025 by [Ricky Hanlon](https://twitter.com/rickhanlonii) + +--- + +<Intro> + +In React Labs posts, we write about projects in active research and development. In this post, we're sharing two new experimental features that are ready to try today, and updates on other areas we're working on now. + +</Intro> + + +Today, we're excited to release documentation for two new experimental features that are ready for testing: + +- [View Transitions](#view-transitions) +- [Activity](#activity) + +We're also sharing updates on new features currently in development: +- [React Performance Tracks](#react-performance-tracks) +- [Compiler IDE Extension](#compiler-ide-extension) +- [Automatic Effect Dependencies](#automatic-effect-dependencies) +- [Fragment Refs](#fragment-refs) +- [Concurrent Stores](#concurrent-stores) + +--- + +# New Experimental Features {/*new-experimental-features*/} + +<Note> + +`<Activity />` has shipped in `react@19.2`. + +`<ViewTransition />` and `addTransitionType` are now available in `react@canary`. + +</Note> + +View Transitions and Activity are now ready for testing in `react@experimental`. These features have been tested in production and are stable, but the final API may still change as we incorporate feedback. + +You can try them by upgrading React packages to the most recent experimental version: + +- `react@experimental` +- `react-dom@experimental` + +Read on to learn how to use these features in your app, or check out the newly published docs: + +- [`<ViewTransition>`](/reference/react/ViewTransition): A component that lets you activate an animation for a Transition. +- [`addTransitionType`](/reference/react/addTransitionType): A function that allows you to specify the cause of a Transition. +- [`<Activity>`](/reference/react/Activity): A component that lets you hide and show parts of the UI. + +## View Transitions {/*view-transitions*/} + +React View Transitions are a new experimental feature that makes it easier to add animations to UI transitions in your app. Under-the-hood, these animations use the new [`startViewTransition`](https://developer.mozilla.org/en-US/docs/Web/API/Document/startViewTransition) API available in most modern browsers. + +To opt-in to animating an element, wrap it in the new `<ViewTransition>` component: + +```js +// "what" to animate. +<ViewTransition> + <div>animate me</div> +</ViewTransition> +``` + +This new component lets you declaratively define "what" to animate when an animation is activated. + +You can define "when" to animate by using one of these three triggers for a View Transition: + +```js +// "when" to animate. + +// Transitions +startTransition(() => setState(...)); + +// Deferred Values +const deferred = useDeferredValue(value); + +// Suspense +<Suspense fallback={<Fallback />}> + <div>Loading...</div> +</Suspense> +``` + +By default, these animations use the [default CSS animations for View Transitions](https://developer.mozilla.org/en-US/docs/Web/API/View_Transition_API/Using#customizing_your_animations) applied (typically a smooth cross-fade). You can use [view transition pseudo-selectors](https://developer.mozilla.org/en-US/docs/Web/API/View_Transition_API/Using#the_view_transition_pseudo-element_tree) to define "how" the animation runs. For example, you can use `*` to change the default animation for all transitions: + +``` +// "how" to animate. +::view-transition-old(*) { + animation: 300ms ease-out fade-out; +} +::view-transition-new(*) { + animation: 300ms ease-in fade-in; +} +``` + +When the DOM updates due to an animation trigger—like `startTransition`, `useDeferredValue`, or a `Suspense` fallback switching to content—React will use [declarative heuristics](/reference/react/ViewTransition#viewtransition) to automatically determine which `<ViewTransition>` components to activate for the animation. The browser will then run the animation that's defined in CSS. + +If you're familiar with the browser's View Transition API and want to know how React supports it, check out [How does `<ViewTransition>` Work](/reference/react/ViewTransition#how-does-viewtransition-work) in the docs. + +In this post, let's take a look at a few examples of how to use View Transitions. + +We'll start with this app, which doesn't animate any of the following interactions: +- Click a video to view the details. +- Click "back" to go back to the feed. +- Type in the list to filter the videos. + +<Sandpack> + +```js src/App.js active +import TalkDetails from './Details'; import Home from './Home'; import {useRouter} from './router'; + +export default function App() { + const {url} = useRouter(); + + // 🚩This version doesn't include any animations yet + return url === '/' ? <Home /> : <TalkDetails />; +} +``` + +```js src/Details.js +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { use, Suspense } from "react"; +import { ChevronLeft } from "./Icons"; + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={video.id} /> + </Suspense> + </div> + </Layout> + ); +} + +``` + +```js src/Home.js +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js +import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {heading} + {isPending && <span className="loader"></span>} + </div> + </div> + + <div className="bottom"> + <div className="content">{children}</div> + </div> + </div> + ); +} +``` + +```js src/LikeButton.js +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js +import { useState } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Thumbnail({ video, children }) { + return ( + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js +import { + useState, + createContext, + use, + useTransition, + useLayoutEffect, + useEffect, +} from "react"; + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +export function Router({ children }) { + const [routerState, setRouterState] = useState({ + pendingNav: () => {}, + url: document.location.pathname, + }); + const [isPending, startTransition] = useTransition(); + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + function navigate(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + function navigateBack(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} +``` + +```css src/styles.css +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +<Note> + +#### View Transitions do not replace CSS and JS driven animations {/*view-transitions-do-not-replace-css-and-js-driven-animations*/} + +View Transitions are meant to be used for UI transitions such as navigation, expanding, opening, or re-ordering. They are not meant to replace all the animations in your app. + +In our example app above, notice that there are already animations when you click the "like" button and in the Suspense fallback glimmer. These are good use cases for CSS animations because they are animating a specific element. + +</Note> + +### Animating navigations {/*animating-navigations*/} + +Our app includes a Suspense-enabled router, with [page transitions already marked as Transitions](/reference/react/useTransition#building-a-suspense-enabled-router), which means navigations are performed with `startTransition`: + +```js +function navigate(url) { + startTransition(() => { + go(url); + }); +} +``` + +`startTransition` is a View Transition trigger, so we can add `<ViewTransition>` to animate between pages: + +```js +// "what" to animate +<ViewTransition key={url}> + {url === '/' ? <Home /> : <TalkDetails />} +</ViewTransition> +``` + +When the `url` changes, the `<ViewTransition>` and new route are rendered. Since the `<ViewTransition>` was updated inside of `startTransition`, the `<ViewTransition>` is activated for an animation. + + +By default, View Transitions include the browser default cross-fade animation. Adding this to our example, we now have a cross-fade whenever we navigate between pages: + +<Sandpack> + +```js src/App.js active +import {ViewTransition} from 'react'; import Details from './Details'; +import Home from './Home'; import {useRouter} from './router'; + +export default function App() { + const {url} = useRouter(); + + // Use ViewTransition to animate between pages. + // No additional CSS needed by default. + return ( + <ViewTransition> + {url === '/' ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { use, Suspense } from "react"; +import { ChevronLeft } from "./Icons"; + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={video.id} /> + </Suspense> + </div> + </Layout> + ); +} + +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {heading} + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Thumbnail({ video, children }) { + return ( + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js +import {useState, createContext,use,useTransition,useLayoutEffect,useEffect} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + + function navigate(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + + + + const [routerState, setRouterState] = useState({ + pendingNav: () => {}, + url: document.location.pathname, + }); + + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + + function navigateBack(url) { + startTransition(() => { + go(url); + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +Since our router already updates the route using `startTransition`, this one line change to add `<ViewTransition>` activates with the default cross-fade animation. + +If you're curious how this works, see the docs for [How does `<ViewTransition>` work?](/reference/react/ViewTransition#how-does-viewtransition-work) + +<Note> + +#### Opting out of `<ViewTransition>` animations {/*opting-out-of-viewtransition-animations*/} + +In this example, we're wrapping the root of the app in `<ViewTransition>` for simplicity, but this means that all transitions in the app will be animated, which can lead to unexpected animations. + +To fix, we're wrapping route children with `"none"` so each page can control its own animation: + +```js +// Layout.js +<ViewTransition default="none"> + {children} +</ViewTransition> +``` + +In practice, navigations should be done via "enter" and "exit" props, or by using Transition Types. + +</Note> + +### Customizing animations {/*customizing-animations*/} + +By default, `<ViewTransition>` includes the default cross-fade from the browser. + +To customize animations, you can provide props to the `<ViewTransition>` component to specify which animations to use, based on [how the `<ViewTransition>` activates](/reference/react/ViewTransition#props). + +For example, we can slow down the `default` cross fade animation: + +```js +<ViewTransition default="slow-fade"> + <Home /> +</ViewTransition> +``` + +And define `slow-fade` in CSS using [view transition classes](/reference/react/ViewTransition#view-transition-class): + +```css +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +Now, the cross fade is slower: + +<Sandpack> + +```js src/App.js active +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Define a default animation of .slow-fade. + // See animations.css for the animation definition. + return ( + <ViewTransition default="slow-fade"> + {url === '/' ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { use, Suspense } from "react"; +import { ChevronLeft } from "./Icons"; + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={video.id} /> + </Suspense> + </div> + </Layout> + ); +} + +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {heading} + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Thumbnail({ video, children }) { + return ( + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import { + useState, + createContext, + use, + useTransition, + useLayoutEffect, + useEffect, +} from "react"; + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +export function Router({ children }) { + const [routerState, setRouterState] = useState({ + pendingNav: () => {}, + url: document.location.pathname, + }); + const [isPending, startTransition] = useTransition(); + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + function navigate(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + function navigateBack(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* Define .slow-fade using view transition classes */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +See [Styling View Transitions](/reference/react/ViewTransition#styling-view-transitions) for a full guide on styling `<ViewTransition>`. + +### Shared Element Transitions {/*shared-element-transitions*/} + +When two pages include the same element, often you want to animate it from one page to the next. + +To do this you can add a unique `name` to the `<ViewTransition>`: + +```js +<ViewTransition name={`video-${video.id}`}> + <Thumbnail video={video} /> +</ViewTransition> +``` + +Now the video thumbnail animates between the two pages: + +<Sandpack> + +```js src/App.js +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Keeping our default slow-fade. + // This allows the content not in the shared + // element transition to cross-fade. + return ( + <ViewTransition default="slow-fade"> + {url === "/" ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { use, Suspense } from "react"; +import { ChevronLeft } from "./Icons"; + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={video.id} /> + </Suspense> + </div> + </Layout> + ); +} + +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {heading} + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js active +import { useState, ViewTransition } from "react"; import LikeButton from "./LikeButton"; import { useRouter } from "./router"; import { PauseIcon, PlayIcon } from "./Icons"; import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import { + useState, + createContext, + use, + useTransition, + useLayoutEffect, + useEffect, +} from "react"; + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +export function Router({ children }) { + const [routerState, setRouterState] = useState({ + pendingNav: () => {}, + url: document.location.pathname, + }); + const [isPending, startTransition] = useTransition(); + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + function navigate(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + function navigateBack(url) { + // Update router state in transition. + startTransition(() => { + go(url); + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* No additional animations needed */ + + + + + + + + + +/* Previously defined animations below */ + + + + + +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +By default, React automatically generates a unique `name` for each element activated for a transition (see [How does `<ViewTransition>` work](/reference/react/ViewTransition#how-does-viewtransition-work)). When React sees a transition where a `<ViewTransition>` with a `name` is removed and a new `<ViewTransition>` with the same `name` is added, it will activate a shared element transition. + +For more info, see the docs for [Animating a Shared Element](/reference/react/ViewTransition#animating-a-shared-element). + +### Animating based on cause {/*animating-based-on-cause*/} + +Sometimes, you may want elements to animate differently based on how it was triggered. For this use case, we've added a new API called `addTransitionType` to specify the cause of a transition: + +```js {4,11} +function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); +} +function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); +} +``` + +With transition types, you can provide custom animations via props to `<ViewTransition>`. Let's add a shared element transition to the header for "6 Videos" and "Back": + +```js {4,5} +<ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} +</ViewTransition> +``` + +Here we pass a `share` prop to define how to animate based on the transition type. When the share transition activates from `nav-forward`, the view transition class `slide-forward` is applied. When it's from `nav-back`, the `slide-back` animation is activated. Let's define these animations in CSS: + +```css +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: ... +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: ... +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: ... +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: ... +} +``` + +Now we can animate the header along with thumbnail based on navigation type: + +<Sandpack> + +```js src/App.js hidden +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Keeping our default slow-fade. + return ( + <ViewTransition default="slow-fade"> + {url === "/" ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { use, Suspense } from "react"; +import { ChevronLeft } from "./Icons"; + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={video.id} /> + </Suspense> + </div> + </Layout> + ); +} + +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js active +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* New keyframes to support our animations above. */ +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + +/* Previously defined animations. */ + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +### Animating Suspense Boundaries {/*animating-suspense-boundaries*/} + +Suspense will also activate View Transitions. + +To animate the fallback to content, we can wrap `Suspense` with `<ViewTranstion>`: + +```js +<ViewTransition> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo /> + </Suspense> +</ViewTransition> +``` + +By adding this, the fallback will cross-fade into the content. Click a video and see the video info animate in: + +<Sandpack> + +```js src/App.js hidden +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Default slow-fade animation. + return ( + <ViewTransition default="slow-fade"> + {url === "/" ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js active +import { use, Suspense, ViewTransition } from "react"; import { fetchVideo, fetchVideoDetails } from "./data"; import { Thumbnail, VideoControls } from "./Videos"; import { useRouter } from "./router"; import Layout from "./Layout"; import { ChevronLeft } from "./Icons"; + +function VideoDetails({ id }) { + // Cross-fade the fallback to content. + return ( + <ViewTransition default="slow-fade"> + <Suspense fallback={<VideoInfoFallback />}> + <VideoInfo id={id} /> + </Suspense> + </ViewTransition> + ); +} + +function VideoInfoFallback() { + return ( + <div> + <div className="fit fallback title"></div> + <div className="fit fallback description"></div> + </div> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <div> + <p className="fit info-title">{details.title}</p> + <p className="fit info-description">{details.description}</p> + </div> + ); +} +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; +import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* Slide the fallback down */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +/* Slide the content up */ +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Define the new keyframes */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +/* Previously defined animations below */ + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +We can also provide custom animations using an `exit` on the fallback, and `enter` on the content: + +```js {3,8} +<Suspense + fallback={ + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } +> + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> +</Suspense> +``` + +Here's how we'll define `slide-down` and `slide-up` with CSS: + +```css {1, 6} +::view-transition-old(.slide-down) { + /* Slide the fallback down */ + animation: ...; +} + +::view-transition-new(.slide-up) { + /* Slide the content up */ + animation: ...; +} +``` + +Now, the Suspense content replaces the fallback with a sliding animation: + +<Sandpack> + +```js src/App.js hidden +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Default slow-fade animation. + return ( + <ViewTransition default="slow-fade"> + {url === "/" ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js active +import { use, Suspense, ViewTransition } from "react"; import { fetchVideo, fetchVideoDetails } from "./data"; import { Thumbnail, VideoControls } from "./Videos"; import { useRouter } from "./router"; import Layout from "./Layout"; import { ChevronLeft } from "./Icons"; + +function VideoDetails({ id }) { + return ( + <Suspense + fallback={ + // Animate the fallback down. + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } + > + {/* Animate the content up */} + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> + </Suspense> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} +``` + +```js src/Home.js hidden +import { Video } from "./Videos"; +import Layout from "./Layout"; +import { fetchVideos } from "./data"; +import { useId, useState, use } from "react"; +import { IconSearch } from "./Icons"; + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(""); + const foundVideos = filterVideos(videos, searchText); + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <div className="video-list"> + {foundVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {foundVideos.map((video) => ( + <Video key={video.id} video={video} /> + ))} + </div> + </div> + </Layout> + ); +} + +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; +import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* Slide the fallback down */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +/* Slide the content up */ +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Define the new keyframes */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +/* Previously defined animations below */ + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + + +### Animating Lists {/*animating-lists*/} + +You can also use `<ViewTransition>` to animate lists of items as they re-order, like in a searchable list of items: + +```js {3,5} +<div className="videos"> + {filteredVideos.map((video) => ( + <ViewTransition key={video.id}> + <Video video={video} /> + </ViewTransition> + ))} +</div> +``` + +To activate the ViewTransition, we can use `useDeferredValue`: + +```js {2} +const [searchText, setSearchText] = useState(''); +const deferredSearchText = useDeferredValue(searchText); +const filteredVideos = filterVideos(videos, deferredSearchText); +``` + +Now the items animate as you type in the search bar: + +<Sandpack> + +```js src/App.js hidden +import { ViewTransition } from "react"; +import Details from "./Details"; +import Home from "./Home"; +import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + // Default slow-fade animation. + return ( + <ViewTransition default="slow-fade"> + {url === "/" ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { use, Suspense, ViewTransition } from "react"; +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { ChevronLeft } from "./Icons"; + +function VideoDetails({id}) { + // Animate from Suspense fallback to content + return ( + <Suspense + fallback={ + // Animate the fallback down. + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } + > + {/* Animate the content up */} + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> + </Suspense> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} +``` + +```js src/Home.js +import { useId, useState, use, useDeferredValue, ViewTransition } from "react";import { Video } from "./Videos";import Layout from "./Layout";import { fetchVideos } from "./data";import { IconSearch } from "./Icons"; + +function SearchList({searchText, videos}) { + // Activate with useDeferredValue ("when") + const deferredSearchText = useDeferredValue(searchText); + const filteredVideos = filterVideos(videos, deferredSearchText); + return ( + <div className="video-list"> + <div className="videos"> + {filteredVideos.map((video) => ( + // Animate each item in list ("what") + <ViewTransition key={video.id}> + <Video video={video} /> + </ViewTransition> + ))} + </div> + {filteredVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + </div> + ); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(''); + + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <SearchList videos={videos} searchText={searchText} /> + </Layout> + ); +} + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; +import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* No additional animations needed */ + + + + + + + + + +/* Previously defined animations below */ + + + + + + +/* Slide animation for Suspense */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +### Final result {/*final-result*/} + +By adding a few `<ViewTransition>` components and a few lines of CSS, we were able to add all the animations above into the final result. + +We're excited about View Transitions and think they will level up the apps you're able to build. They're ready to start trying today in the experimental channel of React releases. + +Let's remove the slow fade, and take a look at the final result: + +<Sandpack> + +```js src/App.js +import {ViewTransition} from 'react'; import Details from './Details'; import Home from './Home'; import {useRouter} from './router'; + +export default function App() { + const {url} = useRouter(); + + // Animate with a cross fade between pages. + return ( + <ViewTransition key={url}> + {url === '/' ? <Home /> : <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js +import { use, Suspense, ViewTransition } from "react"; import { fetchVideo, fetchVideoDetails } from "./data"; import { Thumbnail, VideoControls } from "./Videos"; import { useRouter } from "./router"; import Layout from "./Layout"; import { ChevronLeft } from "./Icons"; + +function VideoDetails({id}) { + // Animate from Suspense fallback to content + return ( + <Suspense + fallback={ + // Animate the fallback down. + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } + > + {/* Animate the content up */} + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> + </Suspense> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} +``` + +```js src/Home.js +import { useId, useState, use, useDeferredValue, ViewTransition } from "react";import { Video } from "./Videos";import Layout from "./Layout";import { fetchVideos } from "./data";import { IconSearch } from "./Icons"; + +function SearchList({searchText, videos}) { + // Activate with useDeferredValue ("when") + const deferredSearchText = useDeferredValue(searchText); + const filteredVideos = filterVideos(videos, deferredSearchText); + return ( + <div className="video-list"> + <div className="videos"> + {filteredVideos.map((video) => ( + // Animate each item in list ("what") + <ViewTransition key={video.id}> + <Video video={video} /> + </ViewTransition> + ))} + </div> + {filteredVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + </div> + ); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(''); + + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <SearchList videos={videos} searchText={searchText} /> + </Layout> + ); +} + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js +import { useState, ViewTransition } from "react"; import LikeButton from "./LikeButton"; import { useRouter } from "./router"; import { PauseIcon, PlayIcon } from "./Icons"; import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + + + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* Slide animations for Suspense the fallback down */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +If you're curious to know more about how they work, check out [How Does `<ViewTransition>` Work](/reference/react/ViewTransition#how-does-viewtransition-work) in the docs. + +_For more background on how we built View Transitions, see: [#31975](https://github.com/react/react/pull/31975), [#32105](https://github.com/react/react/pull/32105), [#32041](https://github.com/react/react/pull/32041), [#32734](https://github.com/react/react/pull/32734), [#32797](https://github.com/react/react/pull/32797) [#31999](https://github.com/react/react/pull/31999), [#32031](https://github.com/react/react/pull/32031), [#32050](https://github.com/react/react/pull/32050), [#32820](https://github.com/react/react/pull/32820), [#32029](https://github.com/react/react/pull/32029), [#32028](https://github.com/react/react/pull/32028), and [#32038](https://github.com/react/react/pull/32038) by [@sebmarkbage](https://twitter.com/sebmarkbage) (thanks Seb!)._ + +--- + +## Activity {/*activity*/} + +<Note> + +**`<Activity />` is now available in React’s Canary channel.** + +[Learn more about React’s release channels here.](/community/versioning-policy#all-release-channels) + +</Note> + +In [past](/blog/2022/06/15/react-labs-what-we-have-been-working-on-june-2022#offscreen) [updates](/blog/2024/02/15/react-labs-what-we-have-been-working-on-february-2024#offscreen-renamed-to-activity), we shared that we were researching an API to allow components to be visually hidden and deprioritized, preserving UI state with reduced performance costs relative to unmounting or hiding with CSS. + +We're now ready to share the API and how it works, so you can start testing it in experimental React versions. + +`<Activity>` is a new component to hide and show parts of the UI: + +```js [[1, 1, "'visible'"], [2, 1, "'hidden'"]] +<Activity mode={isVisible ? 'visible' : 'hidden'}> + <Page /> +</Activity> +``` + +When an Activity is <CodeStep step={1}>visible</CodeStep> it's rendered as normal. When an Activity is <CodeStep step={2}>hidden</CodeStep> it is unmounted, but will save its state and continue to render at a lower priority than anything visible on screen. + +You can use `Activity` to save state for parts of the UI the user isn't using, or pre-render parts that a user is likely to use next. + +Let's look at some examples improving the View Transition examples above. + +<Note> + +**Effects don’t mount when an Activity is hidden.** + +When an `<Activity>` is `hidden`, Effects are unmounted. Conceptually, the component is unmounted, but React saves the state for later. + +In practice, this works as expected if you have followed the [You Might Not Need an Effect](/learn/you-might-not-need-an-effect) guide. To eagerly find problematic Effects, we recommend adding [`<StrictMode>`](/reference/react/StrictMode) which will eagerly perform Activity unmounts and mounts to catch any unexpected side effects. + +</Note> + +### Restoring state with Activity {/*restoring-state-with-activity*/} + +When a user navigates away from a page, it's common to stop rendering the old page: + +```js {6,7} +function App() { + const { url } = useRouter(); + + return ( + <> + {url === '/' && <Home />} + {url !== '/' && <Details />} + </> + ); +} +``` + +However, this means if the user goes back to the old page, all of the previous state is lost. For example, if the `<Home />` page has an `<input>` field, when the user leaves the page the `<input>` is unmounted, and all of the text they had typed is lost. + +Activity allows you to keep the state around as the user changes pages, so when they come back they can resume where they left off. This is done by wrapping part of the tree in `<Activity>` and toggling the `mode`: + +```js {6-8} +function App() { + const { url } = useRouter(); + + return ( + <> + <Activity mode={url === '/' ? 'visible' : 'hidden'}> + <Home /> + </Activity> + {url !== '/' && <Details />} + </> + ); +} +``` + +With this change, we can improve on our View Transitions example above. Before, when you searched for a video, selected one, and returned, your search filter was lost. With Activity, your search filter is restored and you can pick up where you left off. + +Try searching for a video, selecting it, and clicking "back": + +<Sandpack> + +```js src/App.js +import { Activity, ViewTransition } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router"; + +export default function App() { + const { url } = useRouter(); + + return ( + // View Transitions know about Activity + <ViewTransition> + {/* Render Home in Activity so we don't lose state */} + <Activity mode={url === '/' ? 'visible' : 'hidden'}> + <Home /> + </Activity> + {url !== '/' && <Details />} + </ViewTransition> + ); +} +``` + +```js src/Details.js hidden +import { use, Suspense, ViewTransition } from "react"; +import { fetchVideo, fetchVideoDetails } from "./data"; +import { Thumbnail, VideoControls } from "./Videos"; +import { useRouter } from "./router"; +import Layout from "./Layout"; +import { ChevronLeft } from "./Icons"; + +function VideoDetails({id}) { + // Animate from Suspense fallback to content + return ( + <Suspense + fallback={ + // Animate the fallback down. + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } + > + {/* Animate the content up */} + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> + </Suspense> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details() { + const { url, navigateBack } = useRouter(); + const videoId = url.split("/").pop(); + const video = use(fetchVideo(videoId)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} +``` + +```js src/Home.js hidden +import { useId, useState, use, useDeferredValue, ViewTransition } from "react";import { Video } from "./Videos";import Layout from "./Layout";import { fetchVideos } from "./data";import { IconSearch } from "./Icons"; + +function SearchList({searchText, videos}) { + // Activate with useDeferredValue ("when") + const deferredSearchText = useDeferredValue(searchText); + const filteredVideos = filterVideos(videos, deferredSearchText); + return ( + <div className="video-list"> + {filteredVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {filteredVideos.map((video) => ( + // Animate each item in list ("what") + <ViewTransition key={video.id}> + <Video video={video} /> + </ViewTransition> + ))} + </div> + </div> + ); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(''); + + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <SearchList videos={videos} searchText={searchText} /> + </Layout> + ); +} + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* No additional animations needed */ + + + + + + + + + +/* Previously defined animations below */ + + + + + + +/* Slide animations for Suspense the fallback down */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +### Pre-rendering with Activity {/*prerender-with-activity*/} + +Sometimes, you may want to prepare the next part of the UI a user is likely to use ahead of time, so it's ready by the time they are ready to use it. This is especially useful if the next route needs to suspend on data it needs to render, because you can help ensure the data is already fetched before the user navigates. + +For example, our app currently needs to suspend to load the data for each video when you select one. We can improve this by rendering all of the pages in a hidden `<Activity>` until the user navigates: + +```js {2,5,8} +<ViewTransition> + <Activity mode={url === '/' ? 'visible' : 'hidden'}> + <Home /> + </Activity> + <Activity mode={url === '/details/1' ? 'visible' : 'hidden'}> + <Details id={id} /> + </Activity> + <Activity mode={url === '/details/1' ? 'visible' : 'hidden'}> + <Details id={id} /> + </Activity> +<ViewTransition> +``` + +With this update, if the content on the next page has time to pre-render, it will animate in without the Suspense fallback. Click a video, and notice that the video title and description on the Details page render immediately, without a fallback: + +<Sandpack> + +```js src/App.js +import { Activity, ViewTransition, use } from "react"; import Details from "./Details"; import Home from "./Home"; import { useRouter } from "./router"; import {fetchVideos} from './data'; + +export default function App() { + const { url } = useRouter(); + const videoId = url.split("/").pop(); + const videos = use(fetchVideos()); + + return ( + <ViewTransition> + {/* Render videos in Activity to pre-render them */} + {videos.map(({id}) => ( + <Activity key={id} mode={videoId === id ? 'visible' : 'hidden'}> + <Details id={id}/> + </Activity> + ))} + <Activity mode={url === '/' ? 'visible' : 'hidden'}> + <Home /> + </Activity> + </ViewTransition> + ); +} +``` + +```js src/Details.js +import { use, Suspense, ViewTransition } from "react"; import { fetchVideo, fetchVideoDetails } from "./data"; import { Thumbnail, VideoControls } from "./Videos"; import { useRouter } from "./router"; import Layout from "./Layout"; import { ChevronLeft } from "./Icons"; + +function VideoDetails({id}) { + // Animate from Suspense fallback to content. + // If this is pre-rendered then the fallback + // won't need to show. + return ( + <Suspense + fallback={ + // Animate the fallback down. + <ViewTransition exit="slide-down"> + <VideoInfoFallback /> + </ViewTransition> + } + > + {/* Animate the content up */} + <ViewTransition enter="slide-up"> + <VideoInfo id={id} /> + </ViewTransition> + </Suspense> + ); +} + +function VideoInfoFallback() { + return ( + <> + <div className="fallback title"></div> + <div className="fallback description"></div> + </> + ); +} + +export default function Details({id}) { + const { url, navigateBack } = useRouter(); + const video = use(fetchVideo(id)); + + return ( + <Layout + heading={ + <div + className="fit back" + onClick={() => { + navigateBack("/"); + }} + > + <ChevronLeft /> Back + </div> + } + > + <div className="details"> + <Thumbnail video={video} large> + <VideoControls /> + </Thumbnail> + <VideoDetails id={video.id} /> + </div> + </Layout> + ); +} + +function VideoInfo({ id }) { + const details = use(fetchVideoDetails(id)); + return ( + <> + <p className="info-title">{details.title}</p> + <p className="info-description">{details.description}</p> + </> + ); +} +``` + +```js src/Home.js hidden +import { useId, useState, use, useDeferredValue, ViewTransition } from "react";import { Video } from "./Videos";import Layout from "./Layout";import { fetchVideos } from "./data";import { IconSearch } from "./Icons"; + +function SearchList({searchText, videos}) { + // Activate with useDeferredValue ("when") + const deferredSearchText = useDeferredValue(searchText); + const filteredVideos = filterVideos(videos, deferredSearchText); + return ( + <div className="video-list"> + {filteredVideos.length === 0 && ( + <div className="no-results">No results</div> + )} + <div className="videos"> + {filteredVideos.map((video) => ( + // Animate each item in list ("what") + <ViewTransition key={video.id}> + <Video video={video} /> + </ViewTransition> + ))} + </div> + </div> + ); +} + +export default function Home() { + const videos = use(fetchVideos()); + const count = videos.length; + const [searchText, setSearchText] = useState(''); + + return ( + <Layout heading={<div className="fit">{count} Videos</div>}> + <SearchInput value={searchText} onChange={setSearchText} /> + <SearchList videos={videos} searchText={searchText} /> + </Layout> + ); +} + +function SearchInput({ value, onChange }) { + const id = useId(); + return ( + <form className="search" onSubmit={(e) => e.preventDefault()}> + <label htmlFor={id} className="sr-only"> + Search + </label> + <div className="search-input"> + <div className="search-icon"> + <IconSearch /> + </div> + <input + type="text" + id={id} + placeholder="Search" + value={value} + onChange={(e) => onChange(e.target.value)} + /> + </div> + </form> + ); +} + +function filterVideos(videos, query) { + const keywords = query + .toLowerCase() + .split(" ") + .filter((s) => s !== ""); + if (keywords.length === 0) { + return videos; + } + return videos.filter((video) => { + const words = (video.title + " " + video.description) + .toLowerCase() + .split(" "); + return keywords.every((kw) => words.some((w) => w.includes(kw))); + }); +} +``` + +```js src/Icons.js hidden +export function ChevronLeft() { + return ( + <svg + className="chevron-left" + xmlns="http://www.w3.org/2000/svg" + width="20" + height="20" + viewBox="0 0 20 20"> + <g fill="none" fillRule="evenodd" transform="translate(-446 -398)"> + <path + fill="currentColor" + fillRule="nonzero" + d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z" + transform="translate(356.5 164.5)" + /> + <polygon points="446 418 466 418 466 398 446 398" /> + </g> + </svg> + ); +} + +export function PauseIcon() { + return ( + <svg + className="control-icon" + style={{padding: '4px'}} + width="100" + height="100" + viewBox="0 0 512 512" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M256 0C114.617 0 0 114.615 0 256s114.617 256 256 256 256-114.615 256-256S397.383 0 256 0zm-32 320c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128zm128 0c0 8.836-7.164 16-16 16h-32c-8.836 0-16-7.164-16-16V192c0-8.836 7.164-16 16-16h32c8.836 0 16 7.164 16 16v128z" + fill="currentColor" + /> + </svg> + ); +} + +export function PlayIcon() { + return ( + <svg + className="control-icon" + width="100" + height="100" + viewBox="0 0 72 72" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <path + fillRule="evenodd" + clipRule="evenodd" + d="M36 69C54.2254 69 69 54.2254 69 36C69 17.7746 54.2254 3 36 3C17.7746 3 3 17.7746 3 36C3 54.2254 17.7746 69 36 69ZM52.1716 38.6337L28.4366 51.5801C26.4374 52.6705 24 51.2235 24 48.9464V23.0536C24 20.7764 26.4374 19.3295 28.4366 20.4199L52.1716 33.3663C54.2562 34.5034 54.2562 37.4966 52.1716 38.6337Z" + fill="currentColor" + /> + </svg> + ); +} +export function Heart({liked, animate}) { + return ( + <> + <svg + className="absolute overflow-visible" + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + <circle + className={`circle ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + cx="12" + cy="12" + r="11.5" + fill="transparent" + strokeWidth="0" + stroke="currentColor" + /> + </svg> + + <svg + className={`heart ${liked ? 'liked' : ''} ${animate ? 'animate' : ''}`} + viewBox="0 0 24 24" + fill="none" + xmlns="http://www.w3.org/2000/svg"> + {liked ? ( + <path + d="M12 23a.496.496 0 0 1-.26-.074C7.023 19.973 0 13.743 0 8.68c0-4.12 2.322-6.677 6.058-6.677 2.572 0 5.108 2.387 5.134 2.41l.808.771.808-.771C12.834 4.387 15.367 2 17.935 2 21.678 2 24 4.558 24 8.677c0 5.06-7.022 11.293-11.74 14.246a.496.496 0 0 1-.26.074V23z" + fill="currentColor" + /> + ) : ( + <path + fillRule="evenodd" + clipRule="evenodd" + d="m12 5.184-.808-.771-.004-.004C11.065 4.299 8.522 2.003 6 2.003c-3.736 0-6 2.558-6 6.677 0 4.47 5.471 9.848 10 13.079.602.43 1.187.82 1.74 1.167A.497.497 0 0 0 12 23v-.003c.09 0 .182-.026.26-.074C16.977 19.97 24 13.737 24 8.677 24 4.557 21.743 2 18 2c-2.569 0-5.166 2.387-5.192 2.413L12 5.184zm-.002 15.525c2.071-1.388 4.477-3.342 6.427-5.47C20.72 12.733 22 10.401 22 8.677c0-1.708-.466-2.855-1.087-3.55C20.316 4.459 19.392 4 18 4c-.726 0-1.63.364-2.5.9-.67.412-1.148.82-1.266.92-.03.025-.037.031-.019.014l-.013.013L12 7.949 9.832 5.88a10.08 10.08 0 0 0-1.33-.977C7.633 4.367 6.728 4.003 6 4.003c-1.388 0-2.312.459-2.91 1.128C2.466 5.826 2 6.974 2 8.68c0 1.726 1.28 4.058 3.575 6.563 1.948 2.127 4.352 4.078 6.423 5.466z" + fill="currentColor" + /> + )} + </svg> + </> + ); +} + +export function IconSearch(props) { + return ( + <svg width="1em" height="1em" viewBox="0 0 20 20"> + <path + d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" + stroke="currentColor" + fill="none" + strokeWidth="2" + fillRule="evenodd" + strokeLinecap="round" + strokeLinejoin="round"></path> + </svg> + ); +} +``` + +```js src/Layout.js hidden +import {ViewTransition} from 'react'; import { useIsNavPending } from "./router"; + +export default function Page({ heading, children }) { + const isPending = useIsNavPending(); + return ( + <div className="page"> + <div className="top"> + <div className="top-nav"> + {/* Custom classes based on transition type. */} + <ViewTransition + name="nav" + share={{ + 'nav-forward': 'slide-forward', + 'nav-back': 'slide-back', + }}> + {heading} + </ViewTransition> + {isPending && <span className="loader"></span>} + </div> + </div> + {/* Opt-out of ViewTransition for the content. */} + {/* Content can define it's own ViewTransition. */} + <ViewTransition default="none"> + <div className="bottom"> + <div className="content">{children}</div> + </div> + </ViewTransition> + </div> + ); +} +``` + +```js src/LikeButton.js hidden +import {useState} from 'react'; +import {Heart} from './Icons'; + +// A hack since we don't actually have a backend. +// Unlike local state, this survives videos being filtered. +const likedVideos = new Set(); + +export default function LikeButton({video}) { + const [isLiked, setIsLiked] = useState(() => likedVideos.has(video.id)); + const [animate, setAnimate] = useState(false); + return ( + <button + className={`like-button ${isLiked && 'liked'}`} + aria-label={isLiked ? 'Unsave' : 'Save'} + onClick={() => { + const nextIsLiked = !isLiked; + if (nextIsLiked) { + likedVideos.add(video.id); + } else { + likedVideos.delete(video.id); + } + setAnimate(true); + setIsLiked(nextIsLiked); + }}> + <Heart liked={isLiked} animate={animate} /> + </button> + ); +} +``` + +```js src/Videos.js hidden +import { useState, ViewTransition } from "react"; +import LikeButton from "./LikeButton"; +import { useRouter } from "./router"; +import { PauseIcon, PlayIcon } from "./Icons"; +import { startTransition } from "react"; + +export function Thumbnail({ video, children }) { + // Add a name to animate with a shared element transition. + // This uses the default animation, no additional css needed. + return ( + <ViewTransition name={`video-${video.id}`}> + <div + aria-hidden="true" + tabIndex={-1} + className={`thumbnail ${video.image}`} + > + {children} + </div> + </ViewTransition> + ); +} + +export function VideoControls() { + const [isPlaying, setIsPlaying] = useState(false); + + return ( + <span + className="controls" + onClick={() => + startTransition(() => { + setIsPlaying((p) => !p); + }) + } + > + {isPlaying ? <PauseIcon /> : <PlayIcon />} + </span> + ); +} + +export function Video({ video }) { + const { navigate } = useRouter(); + + return ( + <div className="video"> + <div + className="link" + onClick={(e) => { + e.preventDefault(); + navigate(`/video/${video.id}`); + }} + > + <Thumbnail video={video}></Thumbnail> + + <div className="info"> + <div className="video-title">{video.title}</div> + <div className="video-description">{video.description}</div> + </div> + </div> + <LikeButton video={video} /> + </div> + ); +} +``` + + +```js src/data.js hidden +const videos = [ + { + id: '1', + title: 'First video', + description: 'Video description', + image: 'blue', + }, + { + id: '2', + title: 'Second video', + description: 'Video description', + image: 'red', + }, + { + id: '3', + title: 'Third video', + description: 'Video description', + image: 'green', + }, + { + id: '4', + title: 'Fourth video', + description: 'Video description', + image: 'purple', + }, + { + id: '5', + title: 'Fifth video', + description: 'Video description', + image: 'yellow', + }, + { + id: '6', + title: 'Sixth video', + description: 'Video description', + image: 'gray', + }, +]; + +let videosCache = new Map(); +let videoCache = new Map(); +let videoDetailsCache = new Map(); +const VIDEO_DELAY = 1; +const VIDEO_DETAILS_DELAY = 1000; +export function fetchVideos() { + if (videosCache.has(0)) { + return videosCache.get(0); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos); + }, VIDEO_DELAY); + }); + videosCache.set(0, promise); + return promise; +} + +export function fetchVideo(id) { + if (videoCache.has(id)) { + return videoCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DELAY); + }); + videoCache.set(id, promise); + return promise; +} + +export function fetchVideoDetails(id) { + if (videoDetailsCache.has(id)) { + return videoDetailsCache.get(id); + } + const promise = new Promise((resolve) => { + setTimeout(() => { + resolve(videos.find((video) => video.id === id)); + }, VIDEO_DETAILS_DELAY); + }); + videoDetailsCache.set(id, promise); + return promise; +} +``` + +```js src/router.js hidden +import {useState, createContext, use, useTransition, useLayoutEffect, useEffect, addTransitionType} from "react"; + +export function Router({ children }) { + const [isPending, startTransition] = useTransition(); + const [routerState, setRouterState] = useState({pendingNav: () => {}, url: document.location.pathname}); + function navigate(url) { + startTransition(() => { + // Transition type for the cause "nav forward" + addTransitionType('nav-forward'); + go(url); + }); + } + function navigateBack(url) { + startTransition(() => { + // Transition type for the cause "nav backward" + addTransitionType('nav-back'); + go(url); + }); + } + + function go(url) { + setRouterState({ + url, + pendingNav() { + window.history.pushState({}, "", url); + }, + }); + } + + useEffect(() => { + function handlePopState() { + // This should not animate because restoration has to be synchronous. + // Even though it's a transition. + startTransition(() => { + setRouterState({ + url: document.location.pathname + document.location.search, + pendingNav() { + // Noop. URL has already updated. + }, + }); + }); + } + window.addEventListener("popstate", handlePopState); + return () => { + window.removeEventListener("popstate", handlePopState); + }; + }, []); + const pendingNav = routerState.pendingNav; + useLayoutEffect(() => { + pendingNav(); + }, [pendingNav]); + + return ( + <RouterContext + value={{ + url: routerState.url, + navigate, + navigateBack, + isPending, + params: {}, + }} + > + {children} + </RouterContext> + ); +} + +const RouterContext = createContext({ url: "/", params: {} }); + +export function useRouter() { + return use(RouterContext); +} + +export function useIsNavPending() { + return use(RouterContext).isPending; +} + +``` + +```css src/styles.css hidden +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Rg.woff2) format("woff2"); + font-weight: 400; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Md.woff2) format("woff2"); + font-weight: 500; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 600; + font-style: normal; + font-display: swap; +} + +@font-face { + font-family: Optimistic Text; + src: url(https://react.dev/fonts/Optimistic_Text_W_Bd.woff2) format("woff2"); + font-weight: 700; + font-style: normal; + font-display: swap; +} + +* { + box-sizing: border-box; +} + +html { + background-image: url(https://react.dev/images/meta-gradient-dark.png); + background-size: 100%; + background-position: -100%; + background-color: rgb(64 71 86); + background-repeat: no-repeat; + height: 100%; + width: 100%; +} + +body { + font-family: Optimistic Text, -apple-system, ui-sans-serif, system-ui, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji; + padding: 10px 0 10px 0; + margin: 0; + display: flex; + justify-content: center; +} + +#root { + flex: 1 1; + height: auto; + background-color: #fff; + border-radius: 10px; + max-width: 450px; + min-height: 600px; + padding-bottom: 10px; +} + +h1 { + margin-top: 0; + font-size: 22px; +} + +h2 { + margin-top: 0; + font-size: 20px; +} + +h3 { + margin-top: 0; + font-size: 18px; +} + +h4 { + margin-top: 0; + font-size: 16px; +} + +h5 { + margin-top: 0; + font-size: 14px; +} + +h6 { + margin-top: 0; + font-size: 12px; +} + +code { + font-size: 1.2em; +} + +ul { + padding-inline-start: 20px; +} + +.sr-only { + position: absolute; + width: 1px; + height: 1px; + padding: 0; + margin: -1px; + overflow: hidden; + clip: rect(0, 0, 0, 0); + white-space: nowrap; + border-width: 0; +} + +.absolute { + position: absolute; +} + +.overflow-visible { + overflow: visible; +} + +.visible { + overflow: visible; +} + +.fit { + width: fit-content; +} + + +/* Layout */ +.page { + display: flex; + flex-direction: column; + height: 100%; +} + +.top-hero { + height: 200px; + display: flex; + justify-content: center; + align-items: center; + background-image: conic-gradient( + from 90deg at -10% 100%, + #2b303b 0deg, + #2b303b 90deg, + #16181d 1turn + ); +} + +.bottom { + flex: 1; + overflow: auto; +} + +.top-nav { + display: flex; + align-items: center; + justify-content: space-between; + margin-bottom: 0; + padding: 0 12px; + top: 0; + width: 100%; + height: 44px; + color: #23272f; + font-weight: 700; + font-size: 20px; + z-index: 100; + cursor: default; +} + +.content { + padding: 0 12px; + margin-top: 4px; +} + + +.loader { + color: #23272f; + font-size: 3px; + width: 1em; + margin-right: 18px; + height: 1em; + border-radius: 50%; + position: relative; + text-indent: -9999em; + animation: loading-spinner 1.3s infinite linear; + animation-delay: 200ms; + transform: translateZ(0); +} + +@keyframes loading-spinner { + 0%, + 100% { + box-shadow: 0 -3em 0 0.2em, + 2em -2em 0 0em, 3em 0 0 -1em, + 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 0; + } + 12.5% { + box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, + 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 25% { + box-shadow: 0 -3em 0 -0.5em, + 2em -2em 0 0, 3em 0 0 0.2em, + 2em 2em 0 0, 0 3em 0 -1em, + -2em 2em 0 -1em, -3em 0 0 -1em, + -2em -2em 0 -1em; + } + 37.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, + -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 50% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, + -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; + } + 62.5% { + box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, + -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; + } + 75% { + box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, + 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; + } + 87.5% { + box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, + 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, + -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; + } +} + +/* LikeButton */ +.like-button { + outline-offset: 2px; + position: relative; + display: flex; + align-items: center; + justify-content: center; + width: 2.5rem; + height: 2.5rem; + cursor: pointer; + border-radius: 9999px; + border: none; + outline: none 2px; + color: #5e687e; + background: none; +} + +.like-button:focus { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); +} + +.like-button:active { + color: #a6423a; + background-color: rgba(166, 66, 58, .05); + transform: scaleX(0.95) scaleY(0.95); +} + +.like-button:hover { + background-color: #f6f7f9; +} + +.like-button.liked { + color: #a6423a; +} + +/* Icons */ +@keyframes circle { + 0% { + transform: scale(0); + stroke-width: 16px; + } + + 50% { + transform: scale(.5); + stroke-width: 16px; + } + + to { + transform: scale(1); + stroke-width: 0; + } +} + +.circle { + color: rgba(166, 66, 58, .5); + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4,0,.2,1); +} + +.circle.liked.animate { + animation: circle .3s forwards; +} + +.heart { + width: 1.5rem; + height: 1.5rem; +} + +.heart.liked { + transform-origin: center; + transition-property: all; + transition-duration: .15s; + transition-timing-function: cubic-bezier(.4, 0, .2, 1); +} + +.heart.liked.animate { + animation: scale .35s ease-in-out forwards; +} + +.control-icon { + color: hsla(0, 0%, 100%, .5); + filter: drop-shadow(0 20px 13px rgba(0, 0, 0, .03)) drop-shadow(0 8px 5px rgba(0, 0, 0, .08)); +} + +.chevron-left { + margin-top: 2px; + rotate: 90deg; +} + + +/* Video */ +.thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 8rem; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.thumbnail.blue { + background-image: conic-gradient(at top right, #c76a15, #087ea4, #2b3491); +} + +.thumbnail.red { + background-image: conic-gradient(at top right, #c76a15, #a6423a, #2b3491); +} + +.thumbnail.green { + background-image: conic-gradient(at top right, #c76a15, #388f7f, #2b3491); +} + +.thumbnail.purple { + background-image: conic-gradient(at top right, #c76a15, #575fb7, #2b3491); +} + +.thumbnail.yellow { + background-image: conic-gradient(at top right, #c76a15, #FABD62, #2b3491); +} + +.thumbnail.gray { + background-image: conic-gradient(at top right, #c76a15, #4E5769, #2b3491); +} + +.video { + display: flex; + flex-direction: row; + gap: 0.75rem; + align-items: center; +} + +.video .link { + display: flex; + flex-direction: row; + flex: 1 1 0; + gap: 0.125rem; + outline-offset: 4px; + cursor: pointer; +} + +.video .info { + display: flex; + flex-direction: column; + justify-content: center; + margin-left: 8px; + gap: 0.125rem; +} + +.video .info:hover { + text-decoration: underline; +} + +.video-title { + font-size: 15px; + line-height: 1.25; + font-weight: 700; + color: #23272f; +} + +.video-description { + color: #5e687e; + font-size: 13px; +} + +/* Details */ +.details .thumbnail { + position: relative; + aspect-ratio: 16 / 9; + display: flex; + overflow: hidden; + flex-direction: column; + justify-content: center; + align-items: center; + border-radius: 0.5rem; + outline-offset: 2px; + width: 100%; + vertical-align: middle; + background-color: #ffffff; + background-size: cover; + user-select: none; +} + +.video-details-title { + margin-top: 8px; +} + +.video-details-speaker { + display: flex; + gap: 8px; + margin-top: 10px +} + +.back { + display: flex; + align-items: center; + margin-left: -5px; + cursor: pointer; +} + +.back:hover { + text-decoration: underline; +} + +.info-title { + font-size: 1.5rem; + font-weight: 700; + line-height: 1.25; + margin: 8px 0 0 0 ; +} + +.info-description { + margin: 8px 0 0 0; +} + +.controls { + cursor: pointer; +} + +.fallback { + background: #f6f7f8 linear-gradient(to right, #e6e6e6 5%, #cccccc 25%, #e6e6e6 35%) no-repeat; + background-size: 800px 104px; + display: block; + line-height: 1.25; + margin: 8px 0 0 0; + border-radius: 5px; + overflow: hidden; + + animation: 1s linear 1s infinite shimmer; + animation-delay: 300ms; + animation-duration: 1s; + animation-fill-mode: forwards; + animation-iteration-count: infinite; + animation-name: shimmer; + animation-timing-function: linear; +} + + +.fallback.title { + width: 130px; + height: 30px; + +} + +.fallback.description { + width: 150px; + height: 21px; +} + +@keyframes shimmer { + 0% { + background-position: -468px 0; + } + + 100% { + background-position: 468px 0; + } +} + +.search { + margin-bottom: 10px; +} +.search-input { + width: 100%; + position: relative; +} + +.search-icon { + position: absolute; + top: 0; + bottom: 0; + inset-inline-start: 0; + display: flex; + align-items: center; + padding-inline-start: 1rem; + pointer-events: none; + color: #99a1b3; +} + +.search-input input { + display: flex; + padding-inline-start: 2.75rem; + padding-top: 10px; + padding-bottom: 10px; + width: 100%; + text-align: start; + background-color: rgb(235 236 240); + outline: 2px solid transparent; + cursor: pointer; + border: none; + align-items: center; + color: rgb(35 39 47); + border-radius: 9999px; + vertical-align: middle; + font-size: 15px; +} + +.search-input input:hover, .search-input input:active { + background-color: rgb(235 236 240/ 0.8); + color: rgb(35 39 47/ 0.8); +} + +/* Home */ +.video-list { + position: relative; +} + +.video-list .videos { + display: flex; + flex-direction: column; + gap: 1rem; + overflow-y: auto; + height: 100%; +} +``` + + +```css src/animations.css +/* No additional animations needed */ + + + + + + + + + +/* Previously defined animations below */ + + + + + + +/* Slide animations for Suspense the fallback down */ +::view-transition-old(.slide-down) { + animation: 150ms ease-out both fade-out, 150ms ease-out both slide-down; +} + +::view-transition-new(.slide-up) { + animation: 210ms ease-in 150ms both fade-in, 400ms ease-in both slide-up; +} + +/* Animations for view transition classed added by transition type */ +::view-transition-old(.slide-forward) { + /* when sliding forward, the "old" page should slide out to left. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-left; +} + +::view-transition-new(.slide-forward) { + /* when sliding forward, the "new" page should slide in from right. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-right; +} + +::view-transition-old(.slide-back) { + /* when sliding back, the "old" page should slide out to right. */ + animation: 150ms cubic-bezier(0.4, 0, 1, 1) both fade-out, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-to-right; +} + +::view-transition-new(.slide-back) { + /* when sliding back, the "new" page should slide in from left. */ + animation: 210ms cubic-bezier(0, 0, 0.2, 1) 150ms both fade-in, + 400ms cubic-bezier(0.4, 0, 0.2, 1) both slide-from-left; +} + +/* Keyframes to support our animations above. */ +@keyframes slide-up { + from { + transform: translateY(10px); + } + to { + transform: translateY(0); + } +} + +@keyframes slide-down { + from { + transform: translateY(0); + } + to { + transform: translateY(10px); + } +} + +@keyframes fade-in { + from { + opacity: 0; + } +} + +@keyframes fade-out { + to { + opacity: 0; + } +} + +@keyframes slide-to-right { + to { + transform: translateX(50px); + } +} + +@keyframes slide-from-right { + from { + transform: translateX(50px); + } + to { + transform: translateX(0); + } +} + +@keyframes slide-to-left { + to { + transform: translateX(-50px); + } +} + +@keyframes slide-from-left { + from { + transform: translateX(-50px); + } + to { + transform: translateX(0); + } +} + +/* Default .slow-fade. */ +::view-transition-old(.slow-fade) { + animation-duration: 500ms; +} + +::view-transition-new(.slow-fade) { + animation-duration: 500ms; +} +``` + +```js src/index.js hidden +import React, {StrictMode} from 'react'; +import {createRoot} from 'react-dom/client'; +import './styles.css'; +import './animations.css'; + +import App from './App'; +import {Router} from './router'; + +const root = createRoot(document.getElementById('root')); +root.render( + <StrictMode> + <Router> + <App /> + </Router> + </StrictMode> +); +``` + +```json package.json hidden +{ + "dependencies": { + "react": "canary", + "react-dom": "canary", + "react-scripts": "latest" + }, + "scripts": { + "start": "react-scripts start", + "build": "react-scripts build", + "test": "react-scripts test --env=jsdom", + "eject": "react-scripts eject" + } +} +``` + +</Sandpack> + +### Server-Side Rendering with Activity {/*server-side-rendering-with-activity*/} + +When using Activity on a page that uses server-side rendering (SSR), there are additional optimizations. + +If part of the page is rendered with `mode="hidden"`, then it will not be included in the SSR response. Instead, React will schedule a client render for the content inside Activity while the rest of the page hydrates, prioritizing the visible content on screen. + +For parts of the UI rendered with `mode="visible"`, React will de-prioritize hydration of content within Activity, similar to how Suspense content is hydrated at a lower priority. If the user interacts with the page, we'll prioritize hydration within the boundary if needed. + +These are advanced use cases, but they show the additional benefits considered with Activity. + +### Future modes for Activity {/*future-modes-for-activity*/} + +In the future, we may add more modes to Activity. + +For example, a common use case is rendering a modal, where the previous "inactive" page is visible behind the "active" modal view. The "hidden" mode does not work for this use case because it's not visible and not included in SSR. + +Instead, we're considering a new mode that would keep the content visible—and included in SSR—but keep it unmounted and de-prioritize updates. This mode may also need to "pause" DOM updates, since it can be distracting to see backgrounded content updating while a modal is open. + +Another mode we're considering for Activity is the ability to automatically destroy state for hidden Activities if there is too much memory being used. Since the component is already unmounted, it may be preferable to destroy state for the least recently used hidden parts of the app rather than consume too many resources. + +These are areas we're still exploring, and we'll share more as we make progress. For more information on what Activity includes today, [check out the docs](/reference/react/Activity). + +--- + +# Features in development {/*features-in-development*/} + +We're also developing features to help solve the common problems below. + +As we iterate on possible solutions, you may see some potential APIs we're testing being shared based on the PRs we are landing. Please keep in mind that as we try different ideas, we often change or remove different solutions after trying them out. + +When the solutions we're working on are shared too early, it can create churn and confusion in the community. To balance being transparent and limiting confusion, we're sharing the problems we're currently developing solutions for, without sharing a particular solution we have in mind. + +As these features progress, we'll announce them on the blog with docs included so you can try them out. + +## React Performance Tracks {/*react-performance-tracks*/} + +We're working on a new set of custom tracks to performance profilers using browser APIs that [allow adding custom tracks](https://developer.chrome.com/docs/devtools/performance/extension) to provide more information about the performance of your React app. + +This feature is still in progress, so we're not ready to publish docs to fully release it as an experimental feature yet. You can get a sneak preview when using an experimental version of React, which will automatically add the performance tracks to profiles: + +<div style={{display: 'flex', justifyContent: 'center', marginBottom: '1rem'}}> + <picture > + <source srcset="/images/blog/react-labs-april-2025/perf_tracks.png" /> + <img className="w-full light-image" src="/images/blog/react-labs-april-2025/perf_tracks.webp" /> + </picture> + <picture > + <source srcset="/images/blog/react-labs-april-2025/perf_tracks_dark.png" /> + <img className="w-full dark-image" src="/images/blog/react-labs-april-2025/perf_tracks_dark.webp" /> + </picture> +</div> + +There are a few known issues we plan to address such as performance, and the scheduler track not always "connecting" work across Suspended trees, so it's not quite ready to try. We're also still collecting feedback from early adopters to improve the design and usability of the tracks. + +Once we solve those issues, we'll publish experimental docs and share that it's ready to try. + +--- + +## Automatic Effect Dependencies {/*automatic-effect-dependencies*/} + +When we released hooks, we had three motivations: + +- **Sharing code between components**: hooks replaced patterns like render props and higher-order components to allow you to reuse stateful logic without changing your component hierarchy. +- **Think in terms of function, not lifecycles**: hooks let you split one component into smaller functions based on what pieces are related (such as setting up a subscription or fetching data), rather than forcing a split based on lifecycle methods. +- **Support ahead-of-time compilation**: hooks were designed to support ahead-of-time compilation with less pitfalls causing unintentional de-optimizations caused by lifecycle methods, and limitations of classes. + +Since their release, hooks have been successful at *sharing code between components*. Hooks are now the favored way to share logic between components, and there are less use cases for render props and higher order components. Hooks have also been successful at supporting features like Fast Refresh that were not possible with class components. + +### Effects can be hard {/*effects-can-be-hard*/} + +Unfortunately, some hooks are still hard to think in terms of function instead of lifecycles. Effects specifically are still hard to understand and are the most common pain point we hear from developers. Last year, we spent a significant amount of time researching how Effects were used, and how those use cases could be simplified and easier to understand. + +We found that often, the confusion is from using an Effect when you don't need to. The [You Might Not Need an Effect](/learn/you-might-not-need-an-effect) guide covers many cases for when Effects are not the right solution. However, even when an Effect is the right fit for a problem, Effects can still be harder to understand than class component lifecycles. + +We believe one of the reasons for confusion is that developers to think of Effects from the _component's_ perspective (like a lifecycle), instead of the _Effects_ point of view (what the Effect does). + +Let's look at an example [from the docs](/learn/lifecycle-of-reactive-effects#thinking-from-the-effects-perspective): + +```js +useEffect(() => { + // Your Effect connected to the room specified with roomId... + const connection = createConnection(serverUrl, roomId); + connection.connect(); + return () => { + // ...until it disconnected + connection.disconnect(); + }; +}, [roomId]); +``` + +Many users would read this code as "on mount, connect to the roomId. whenever `roomId` changes, disconnect to the old room and re-create the connection". However, this is thinking from the component's lifecycle perspective, which means you will need to think of every component lifecycle state to write the Effect correctly. This can be difficult, so it's understandable that Effects seem harder than class lifecycles when using the component perspective. + +### Effects without dependencies {/*effects-without-dependencies*/} + +Instead, it's better to think from the Effect's perspective. The Effect doesn't know about the component lifecycles. It only describes how to start synchronization and how to stop it. When users think of Effects in this way, their Effects tend to be easier to write, and more resilient to being started and stopped as many times as is needed. + +We spent some time researching why Effects are thought of from the component perspective, and we think one of the reasons is the dependency array. Since you have to write it, it's right there and in your face reminding you of what you're "reacting" to and baiting you into the mental model of 'do this when these values change'. + +When we released hooks, we knew we could make them easier to use with ahead-of-time compilation. With the React Compiler, you're now able to avoid writing `useCallback` and `useMemo` yourself in most cases. For Effects, the compiler can insert the dependencies for you: + +```js +useEffect(() => { + const connection = createConnection(serverUrl, roomId); + connection.connect(); + return () => { + connection.disconnect(); + }; +}); // compiler inserted dependencies. +``` + +With this code, the React Compiler can infer the dependencies for you and insert them automatically so you don't need to see or write them. With features like [the IDE extension](#compiler-ide-extension) and [`useEffectEvent`](/reference/react/useEffectEvent), we can provide a CodeLens to show you what the Compiler inserted for times you need to debug, or to optimize by removing a dependency. This helps reinforce the correct mental model for writing Effects, which can run at any time to synchronize your component or hook's state with something else. + +Our hope is that automatically inserting dependencies is not only easier to write, but that it also makes them easier to understand by forcing you to think in terms of what the Effect does, and not in component lifecycles. + +--- + +## Compiler IDE Extension {/*compiler-ide-extension*/} + +Later in 2025 [we shared](/blog/2025/10/07/react-compiler-1) the first stable release of React Compiler, and we're continuing to invest in shipping more improvements. + +We've also begun exploring ways to use the React Compiler to provide information that can improve understanding and debugging your code. One idea we've started exploring is a new experimental LSP-based React IDE extension powered by React Compiler, similar to the extension used in [Lauren Tan's React Conf talk](https://conf2024.react.dev/talks/5). + +Our idea is that we can use the compiler's static analysis to provide more information, suggestions, and optimization opportunities directly in your IDE. For example, we can provide diagnostics for code breaking the Rules of React, hovers to show if components and hooks were optimized by the compiler, or a CodeLens to see [automatically inserted Effect dependencies](#automatic-effect-dependencies). + +The IDE extension is still an early exploration, but we'll share our progress in future updates. + +--- + +## Fragment Refs {/*fragment-refs*/} + +Many DOM APIs like those for event management, positioning, and focus are difficult to compose when writing with React. This often leads developers to reach for Effects, managing multiple Refs, by using APIs like `findDOMNode` (removed in React 19). + +We are exploring adding refs to Fragments that would point to a group of DOM elements, rather than just a single element. Our hope is that this will simplify managing multiple children and make it easier to write composable React code when calling DOM APIs. + +Fragment refs are still being researched. We'll share more when we're closer to having the final API finished. + +--- + +## Gesture Animations {/*gesture-animations*/} + +We're also researching ways to enhance View Transitions to support gesture animations such as swiping to open a menu, or scroll through a photo carousel. + +Gestures present new challenges for a few reasons: + +- **Gestures are continuous**: as you swipe the animation is tied to your finger placement time, rather than triggering and running to completion. +- **Gestures don't complete**: when you release your finger gesture animations can run to completion, or revert to their original state (like when you only partially open a menu) depending on how far you go. +- **Gestures invert old and new**: while you're animating, you want the page you are animating from to stay "alive" and interactive. This inverts the browser View Transition model where the "old" state is a snapshot and the "new" state is the live DOM. + +We believe we’ve found an approach that works well and may introduce a new API for triggering gesture transitions. For now, we're focused on shipping `<ViewTransition>`, and will revisit gestures afterward. + +--- + +## Concurrent Stores {/*concurrent-stores*/} + +When we released React 18 with concurrent rendering, we also released `useSyncExternalStore` so external store libraries that did not use React state or context could [support concurrent rendering](https://github.com/reactwg/react-18/discussions/70) by forcing a synchronous render when the store is updated. + +Using `useSyncExternalStore` comes at a cost though, since it forces a bail out from concurrent features like transitions, and forces existing content to show Suspense fallbacks. + +Now that React 19 has shipped, we're revisiting this problem space to create a primitive to fully support concurrent external stores with the `use` API: + +```js +const value = use(store); +``` + +Our goal is to allow external state to be read during render without tearing, and to work seamlessly with all of the concurrent features React offers. + +This research is still early. We'll share more, and what the new APIs will look like, when we're further along. + +--- + +_Thanks to [Aurora Scharff](https://bsky.app/profile/aurorascharff.no), [Dan Abramov](https://bsky.app/profile/danabra.mov), [Eli White](https://twitter.com/Eli_White), [Lauren Tan](https://bsky.app/profile/no.lol), [Luna Wei](https://github.com/lunaleaps), [Matt Carroll](https://twitter.com/mattcarrollcode), [Jack Pope](https://jackpope.me), [Jason Bonta](https://threads.net/someextent), [Jordan Brown](https://github.com/jbrown215), [Jordan Eldredge](https://bsky.app/profile/capt.dev), [Mofei Zhang](https://threads.net/z_mofei), [Sebastien Lorber](https://bsky.app/profile/sebastienlorber.com), [Sebastian Markbåge](https://bsky.app/profile/sebmarkbage.calyptus.eu), and [Tim Yung](https://github.com/yungsters) for reviewing this post._ diff --git a/src/content/blog/2025/10/01/react-19-2.md b/src/content/blog/2025/10/01/react-19-2.md new file mode 100644 index 000000000..feee6cdb6 --- /dev/null +++ b/src/content/blog/2025/10/01/react-19-2.md @@ -0,0 +1,339 @@ +--- +title: "React 19.2" +author: The React Team +date: 2025/10/01 +description: React 19.2 adds new features like Activity, React Performance Tracks, useEffectEvent, and more. +--- + +October 1, 2025 by [The React Team](/community/team) + +--- + +<Intro> + +React 19.2 is now available on npm! + +</Intro> + +This is our third release in the last year, following React 19 in December and React 19.1 in June. In this post, we'll give an overview of the new features in React 19.2, and highlight some notable changes. + +<InlineToc /> + +--- + +## New React Features {/*new-react-features*/} + +### `<Activity />` {/*activity*/} + +`<Activity>` lets you break your app into "activities" that can be controlled and prioritized. + +You can use Activity as an alternative to conditionally rendering parts of your app: + +```js +// Before +{isVisible && <Page />} + +// After +<Activity mode={isVisible ? 'visible' : 'hidden'}> + <Page /> +</Activity> +``` + +In React 19.2, Activity supports two modes: `visible` and `hidden`. + +- `hidden`: hides the children, unmounts effects, and defers all updates until React has nothing left to work on. +- `visible`: shows the children, mounts effects, and allows updates to be processed normally. + +This means you can pre-render and keep rendering hidden parts of the app without impacting the performance of anything visible on screen. + +You can use Activity to render hidden parts of the app that a user is likely to navigate to next, or to save the state of parts the user navigates away from. This helps make navigations quicker by loading data, css, and images in the background, and allows back navigations to maintain state such as input fields. + +In the future, we plan to add more modes to Activity for different use cases. + +For examples on how to use Activity, check out the [Activity docs](/reference/react/Activity). + +--- + +### `useEffectEvent` {/*use-effect-event*/} + +One common pattern with `useEffect` is to notify the app code about some kind of "events" from an external system. For example, when a chat room gets connected, you might want to display a notification: + +```js {5,11} +function ChatRoom({ roomId, theme }) { + useEffect(() => { + const connection = createConnection(serverUrl, roomId); + connection.on('connected', () => { + showNotification('Connected!', theme); + }); + connection.connect(); + return () => { + connection.disconnect() + }; + }, [roomId, theme]); + // ... +``` + +The problem with the code above is that a change to any values used inside such an "event" will cause the surrounding Effect to re-run. For example, changing the `theme` will cause the chat room to reconnect. This makes sense for values related to the Effect logic itself, like `roomId`, but it doesn't make sense for `theme`. + +To solve this, most users just disable the lint rule and exclude the dependency. But that can lead to bugs since the linter can no longer help you keep the dependencies up to date if you need to update the Effect later. + +With `useEffectEvent`, you can split the "event" part of this logic out of the Effect that emits it: + +```js {2,3,4,9} +function ChatRoom({ roomId, theme }) { + const onConnected = useEffectEvent(() => { + showNotification('Connected!', theme); + }); + + useEffect(() => { + const connection = createConnection(serverUrl, roomId); + connection.on('connected', () => { + onConnected(); + }); + connection.connect(); + return () => connection.disconnect(); + }, [roomId]); // ✅ All dependencies declared (Effect Events aren't dependencies) + // ... +``` + +Similar to DOM events, Effect Events always “see” the latest props and state. + +**Effect Events should _not_ be declared in the dependency array**. You'll need to upgrade to `eslint-plugin-react-hooks@latest` so that the linter doesn't try to insert them as dependencies. Note that Effect Events can only be declared in the same component or Hook as "their" Effect. These restrictions are verified by the linter. + +<Note> + +#### When to use `useEffectEvent` {/*when-to-use-useeffectevent*/} + +You should use `useEffectEvent` for functions that are conceptually "events" that happen to be fired from an Effect instead of a user event (that's what makes it an "Effect Event"). You don't need to wrap everything in `useEffectEvent`, or to use it just to silence the lint error, as this can lead to bugs. + +For a deep dive on how to think about Event Effects, see: [Separating Events from Effects](/learn/separating-events-from-effects#extracting-non-reactive-logic-out-of-effects). + +</Note> + +--- + +### `cacheSignal` {/*cache-signal*/} + +<RSC> + +`cacheSignal` is only for use with [React Server Components](/reference/rsc/server-components). + +</RSC> + +`cacheSignal` allows you to know when the [`cache()`](/reference/react/cache) lifetime is over: + +``` +import {cache, cacheSignal} from 'react'; +const dedupedFetch = cache(fetch); + +async function Component() { + await dedupedFetch(url, { signal: cacheSignal() }); +} +``` + +This allows you to clean up or abort work when the result will no longer be used in the cache, such as: + +- React has successfully completed rendering +- The render was aborted +- The render has failed + +For more info, see the [`cacheSignal` docs](/reference/react/cacheSignal). + +--- + +### Performance Tracks {/*performance-tracks*/} + +React 19.2 adds a new set of [custom tracks](https://developer.chrome.com/docs/devtools/performance/extension) to Chrome DevTools performance profiles to provide more information about the performance of your React app: + +<div style={{display: 'flex', justifyContent: 'center', marginBottom: '1rem'}}> + <picture > + <source srcset="/images/blog/react-labs-april-2025/perf_tracks.png" /> + <img className="w-full light-image" src="/images/blog/react-labs-april-2025/perf_tracks.webp" /> + </picture> + <picture > + <source srcset="/images/blog/react-labs-april-2025/perf_tracks_dark.png" /> + <img className="w-full dark-image" src="/images/blog/react-labs-april-2025/perf_tracks_dark.webp" /> + </picture> +</div> + +The [React Performance Tracks docs](/reference/dev-tools/react-performance-tracks) explain everything included in the tracks, but here is a high-level overview. + +#### Scheduler ⚛ {/*scheduler-*/} + +The Scheduler track shows what React is working on for different priorities such as "blocking" for user interactions, or "transition" for updates inside startTransition. Inside each track, you will see the type of work being performed such as the event that scheduled an update, and when the render for that update happened. + +We also show information such as when an update is blocked waiting for a different priority, or when React is waiting for paint before continuing. The Scheduler track helps you understand how React splits your code into different priorities, and the order it completed the work. + +See the [Scheduler track](/reference/dev-tools/react-performance-tracks#scheduler) docs to see everything included. + +#### Components ⚛ {/*components-*/} + +The Components track shows the tree of components that React is working on either to render or run effects. Inside you'll see labels such as "Mount" for when children mount or effects are mounted, or "Blocked" for when rendering is blocked due to yielding to work outside React. + +The Components track helps you understand when components are rendered or run effects, and the time it takes to complete that work to help identify performance problems. + +See the [Components track docs](/reference/dev-tools/react-performance-tracks#components) for see everything included. + +--- + +## New React DOM Features {/*new-react-dom-features*/} + +### Partial Pre-rendering {/*partial-pre-rendering*/} + +In 19.2 we're adding a new capability to pre-render part of the app ahead of time, and resume rendering it later. + +This feature is called "Partial Pre-rendering", and allows you to pre-render the static parts of your app and serve it from a CDN, and then resume rendering the shell to fill it in with dynamic content later. + +To pre-render an app to resume later, first call `prerender` with an `AbortController`: + +``` +const {prelude, postponed} = await prerender(<App />, { + signal: controller.signal, +}); + +// Save the postponed state for later +await savePostponedState(postponed); + +// Send prelude to client or CDN. +``` + +Then, you can return the `prelude` shell to the client, and later call `resume` to "resume" to a SSR stream: + +``` +const postponed = await getPostponedState(request); +const resumeStream = await resume(<App />, postponed); + +// Send stream to client. +``` + +Or you can call `resumeAndPrerender` to resume to get static HTML for SSG: + +``` +const postponedState = await getPostponedState(request); +const { prelude } = await resumeAndPrerender(<App />, postponedState); + +// Send complete HTML prelude to CDN. +``` + +For more info, see the docs for the new APIs: +- `react-dom/server` + - [`resume`](/reference/react-dom/server/resume): for Web Streams. + - [`resumeToPipeableStream`](/reference/react-dom/server/resumeToPipeableStream) for Node Streams. +- `react-dom/static` + - [`resumeAndPrerender`](/reference/react-dom/static/resumeAndPrerender) for Web Streams. + - [`resumeAndPrerenderToNodeStream`](/reference/react-dom/static/resumeAndPrerenderToNodeStream) for Node Streams. + +Additionally, the prerender apis now return a `postpone` state to pass to the `resume` apis. + +--- + +## Notable Changes {/*notable-changes*/} + +### Batching Suspense Boundaries for SSR {/*batching-suspense-boundaries-for-ssr*/} + +We fixed a behavioral bug where Suspense boundaries would reveal differently depending on if they were rendered on the client or when streaming from server-side rendering. + +Starting in 19.2, React will batch reveals of server-rendered Suspense boundaries for a short time, to allow more content to be revealed together and align with the client-rendered behavior. + +<Diagram name="19_2_batching_before" height={162} width={1270} alt="Diagram with three sections, with an arrow transitioning each section in between. The first section contains a page rectangle showing a glimmer loading state with faded bars. The second panel shows the top half of the page revealed and highlighted in blue. The third panel shows the entire the page revealed and highlighted in blue."> + +Previously, during streaming server-side rendering, suspense content would immediately replace fallbacks. + +</Diagram> + +<Diagram name="19_2_batching_after" height={162} width={1270} alt="Diagram with three sections, with an arrow transitioning each section in between. The first section contains a page rectangle showing a glimmer loading state with faded bars. The second panel shows the same page. The third panel shows the entire the page revealed and highlighted in blue."> + +In React 19.2, suspense boundaries are batched for a small amount of time, to allow revealing more content together. + +</Diagram> + +This fix also prepares apps for supporting `<ViewTransition>` for Suspense during SSR. By revealing more content together, animations can run in larger batches of content, and avoid chaining animations of content that stream in close together. + +<Note> + +React uses heuristics to ensure throttling does not impact core web vitals and search ranking. + +For example, if the total page load time is approaching 2.5s (which is the time considered "good" for [LCP](https://web.dev/articles/lcp)), React will stop batching and reveal content immediately so that the throttling is not the reason to miss the metric. + +</Note> + +--- + +### SSR: Web Streams support for Node {/*ssr-web-streams-support-for-node*/} + +React 19.2 adds support for Web Streams for streaming SSR in Node.js: +- [`renderToReadableStream`](/reference/react-dom/server/renderToReadableStream) is now available for Node.js +- [`prerender`](/reference/react-dom/static/prerender) is now available for Node.js + +As well as the new `resume` APIs: +- [`resume`](/reference/react-dom/server/resume) is available for Node.js. +- [`resumeAndPrerender`](/reference/react-dom/static/resumeAndPrerender) is available for Node.js. + + +<Pitfall> + +#### Prefer Node Streams for server-side rendering in Node.js {/*prefer-node-streams-for-server-side-rendering-in-nodejs*/} + +In Node.js environments, we still highly recommend using the Node Streams APIs: + +- [`renderToPipeableStream`](/reference/react-dom/server/renderToPipeableStream) +- [`resumeToPipeableStream`](/reference/react-dom/server/resumeToPipeableStream) +- [`prerenderToNodeStream`](/reference/react-dom/static/prerenderToNodeStream) +- [`resumeAndPrerenderToNodeStream`](/reference/react-dom/static/resumeAndPrerenderToNodeStream) + +This is because Node Streams are much faster than Web Streams in Node, and Web Streams do not support compression by default, leading to users accidentally missing the benefits of streaming. + +</Pitfall> + +--- + +### `eslint-plugin-react-hooks` v6 {/*eslint-plugin-react-hooks*/} + +We also published `eslint-plugin-react-hooks@latest` with flat config by default in the `recommended` preset, and opt-in for new React Compiler powered rules. + +To continue using the legacy config, you can change to `recommended-legacy`: + +```diff +- extends: ['plugin:react-hooks/recommended'] ++ extends: ['plugin:react-hooks/recommended-legacy'] +``` + +For a full list of compiler enabled rules, [check out the linter docs](/reference/eslint-plugin-react-hooks#recommended). + +Check out the `eslint-plugin-react-hooks` [changelog for a full list of changes](https://github.com/react/react/blob/main/packages/eslint-plugin-react-hooks/CHANGELOG.md#610). + +--- + +### Update the default `useId` prefix {/*update-the-default-useid-prefix*/} + +In 19.2, we're updating the default `useId` prefix from `:r:` (19.0.0) or `«r»` (19.1.0) to `_r_`. + +The original intent of using a special character that was not valid for CSS selectors was that it would be unlikely to collide with IDs written by users. However, to support View Transitions, we need to ensure that IDs generated by `useId` are valid for `view-transition-name` and XML 1.0 names. + +--- + +## Changelog {/*changelog*/} + +Other notable changes +- `react-dom`: Allow nonce to be used on hoistable styles [#32461](https://github.com/react/react/pull/32461) +- `react-dom`: Warn for using a React owned node as a Container if it also has text content [#32774](https://github.com/react/react/pull/32774) + +Notable bug fixes +- `react`: Stringify context as "SomeContext" instead of "SomeContext.Provider" [#33507](https://github.com/react/react/pull/33507) +- `react`: Fix infinite useDeferredValue loop in popstate event [#32821](https://github.com/react/react/pull/32821) +- `react`: Fix a bug when an initial value was passed to useDeferredValue [#34376](https://github.com/react/react/pull/34376) +- `react`: Fix a crash when submitting forms with Client Actions [#33055](https://github.com/react/react/pull/33055) +- `react`: Hide/unhide the content of dehydrated suspense boundaries if they resuspend [#32900](https://github.com/react/react/pull/32900) +- `react`: Avoid stack overflow on wide trees during Hot Reload [#34145](https://github.com/react/react/pull/34145) +- `react`: Improve component stacks in various places [#33629](https://github.com/react/react/pull/33629), [#33724](https://github.com/react/react/pull/33724), [#32735](https://github.com/react/react/pull/32735), [#33723](https://github.com/react/react/pull/33723) +- `react`: Fix a bug with React.use inside React.lazy-ed Component [#33941](https://github.com/react/react/pull/33941) +- `react-dom`: Stop warning when ARIA 1.3 attributes are used [#34264](https://github.com/react/react/pull/34264) +- `react-dom`: Fix a bug with deeply nested Suspense inside Suspense fallbacks [#33467](https://github.com/react/react/pull/33467) +- `react-dom`: Avoid hanging when suspending after aborting while rendering [#34192](https://github.com/react/react/pull/34192) + +For a full list of changes, please see the [Changelog](https://github.com/react/react/blob/main/CHANGELOG.md). + + +--- + +_Thanks to [Ricky Hanlon](https://bsky.app/profile/ricky.fm) for [writing this post](https://www.youtube.com/shorts/T9X3YkgZRG0), [Dan Abramov](https://bsky.app/profile/danabra.mov), [Matt Carroll](https://twitter.com/mattcarrollcode), [Jack Pope](https://jackpope.me), and [Joe Savona](https://x.com/en_JS) for reviewing this post._ diff --git a/src/content/blog/2025/10/07/react-compiler-1.md b/src/content/blog/2025/10/07/react-compiler-1.md new file mode 100644 index 000000000..ee5ffa4fd --- /dev/null +++ b/src/content/blog/2025/10/07/react-compiler-1.md @@ -0,0 +1,194 @@ +--- +title: "React Compiler v1.0" +author: Lauren Tan, Joe Savona, and Mofei Zhang +date: 2025/10/07 +description: We are releasing the compiler's first stable release today. + +--- + +Oct 7, 2025 by [Lauren Tan](https://x.com/potetotes), [Joe Savona](https://x.com/en_JS), and [Mofei Zhang](https://x.com/zmofei). + +--- + +<Intro> + +The React team is excited to share new updates: + +</Intro> + +1. React Compiler 1.0 is available today. +2. Compiler-powered lint rules ship in `eslint-plugin-react-hooks`'s `recommended` and `recommended-latest` preset. +3. We've published an incremental adoption guide, and partnered with Expo, Vite, and Next.js so new apps can start with the compiler enabled. + +--- + +We are releasing the compiler's first stable release today. React Compiler works on both React and React Native, and automatically optimizes components and hooks without requiring rewrites. The compiler has been battle tested on major apps at Meta and is fully production-ready. + +[React Compiler](/learn/react-compiler) is a build-time tool that optimizes your React app through automatic memoization. Last year, we published React Compiler's [first beta](/blog/2024/10/21/react-compiler-beta-release) and received lots of great feedback and contributions. We're excited about the wins we've seen from folks adopting the compiler (see case studies from [Sanity Studio](https://github.com/reactwg/react-compiler/discussions/33) and [Wakelet](https://github.com/reactwg/react-compiler/discussions/52)) and are excited to bring the compiler to more users in the React community. + +This release is the culmination of a huge and complex engineering effort spanning almost a decade. The React team's first exploration into compilers started with [Prepack](https://github.com/facebookarchive/prepack) in 2017. While this project was eventually shut down, there were many learnings that informed the team on the design of Hooks, which were designed with a future compiler in mind. In 2021, [Xuan Huang](https://x.com/Huxpro) demoed the [first iteration](https://www.youtube.com/watch?v=lGEMwh32soc) of a new take on React Compiler. + +Although this first version of the new React Compiler was eventually rewritten, the first prototype gave us increased confidence that this was a tractable problem, and the learnings that an alternative compiler architecture could precisely give us the memoization characteristics we wanted. [Joe Savona](https://x.com/en_JS), [Sathya Gunasekaran](https://x.com/_gsathya), [Mofei Zhang](https://x.com/zmofei), and [Lauren Tan](https://x.com/potetotes) worked through our first rewrite, moving the compiler's architecture into a Control Flow Graph (CFG) based High-Level Intermediate Representation (HIR). This paved the way for much more precise analysis and even type inference within React Compiler. Since then, many significant portions of the compiler have been rewritten, with each rewrite informed by our learnings from the previous attempt. And we have received significant help and contributions from many members of the [React team](/community/team) along the way. + +This stable release is our first of many. The compiler will continue to evolve and improve, and we expect to see it become a new foundation and era for the next decade and more of React. + +You can jump straight to the [quickstart](/learn/react-compiler), or read on for the highlights from React Conf 2025. + +<DeepDive> + +#### How does React Compiler work? {/*how-does-react-compiler-work*/} + +React Compiler is an optimizing compiler that optimizes components and hooks through automatic memoization. While it is implemented as a Babel plugin currently, the compiler is largely decoupled from Babel and lowers the Abstract Syntax Tree (AST) provided by Babel into its own novel HIR, and through multiple compiler passes, carefully understands data-flow and mutability of your React code. This allows the compiler to granularly memoize values used in rendering, including the ability to memoize conditionally, which is not possible through manual memoization. + +```js {8} +import { use } from 'react'; + +export default function ThemeProvider(props) { + if (!props.children) { + return null; + } + // The compiler can still memoize code after a conditional return + const theme = mergeTheme(props.theme, use(ThemeContext)); + return ( + <ThemeContext value={theme}> + {props.children} + </ThemeContext> + ); +} +``` +_See this example in the [React Compiler Playground](https://playground.react.dev/#N4Igzg9grgTgxgUxALhASwLYAcIwC4AEwBUYCBAvgQGYwQYEDkMCAhnHowNwA6AdvwQAPHPgIATBNVZQANoWpQ+HNBD4EAKgAsEGBAAU6ANzSSYACix0sYAJRF+BAmmoFzAQisQbAOjha0WXEWPntgRycCFjxYdT45WV51Sgi4NTBCPB09AgBeAj0YAHMEbV0ES2swHyzygBoSMnMyvQBhNTxhPFtbJKdo2LcIpwAeFoR2vk6hQiNWWSgEXOBavQoAPmHI4C9ff0DghD4KLZGAenHJ6bxN5N7+ChA6kDS+ajQilHRsXEyATyw5GI+gWRTQfAA8lg8Ko+GBKDQ6AxGAAjVgohCyAC0WFB4KxLHYeCxaWwgQQMDO4jQGW4-H45nCyTOZ1JWECrBhagAshBJMgCDwQPNZEKHgQwJyae8EPCQVAwZDobC7FwnuAtBAAO4ASSmFL48zAKGksjIFCAA)_ + +In addition to automatic memoization, React Compiler also has validation passes that run on your React code. These passes encode the [Rules of React](/reference/rules), and uses the compiler's understanding of data-flow and mutability to provide diagnostics where the Rules of React are broken. These diagnostics often expose latent bugs hiding in React code, and are primarily surfaced through `eslint-plugin-react-hooks`. + +To learn more about how the compiler optimizes your code, visit the [Playground](https://playground.react.dev). + +</DeepDive> + +## Use React Compiler Today {/*use-react-compiler-today*/} +To install the compiler: + +npm +<TerminalBlock> +npm install --save-dev --save-exact babel-plugin-react-compiler@latest +</TerminalBlock> + +pnpm +<TerminalBlock> +pnpm add --save-dev --save-exact babel-plugin-react-compiler@latest +</TerminalBlock> + +yarn +<TerminalBlock> +yarn add --dev --exact babel-plugin-react-compiler@latest +</TerminalBlock> + +As part of the stable release, we've been making React Compiler easier to add to your projects and added optimizations to how the compiler generates memoization. React Compiler now supports optional chains and array indices as dependencies. These improvements ultimately result in fewer re-renders and more responsive UIs, while letting you keep writing idiomatic declarative code. + +You can find more details on using the Compiler in [our docs](/learn/react-compiler). + +## What we're seeing in production {/*react-compiler-at-meta*/} +[The compiler has already shipped in apps like Meta Quest Store](https://youtu.be/lyEKhv8-3n0?t=3002). We've seen initial loads and cross-page navigations improve by up to 12%, while certain interactions are more than 2.5× faster. Memory usage stays neutral even with these wins. Although your mileage may vary, we recommend experimenting with the compiler in your app to see similar performance gains. + +## Backwards Compatibility {/*backwards-compatibility*/} +As noted in the Beta announcement, React Compiler is compatible with React 17 and up. If you are not yet on React 19, you can use React Compiler by specifying a minimum target in your compiler config, and adding `react-compiler-runtime` as a dependency. You can find docs on this [here](/reference/react-compiler/target#targeting-react-17-or-18). + +## Enforce the Rules of React with compiler-powered linting {/*migrating-from-eslint-plugin-react-compiler-to-eslint-plugin-react-hooks*/} +React Compiler includes an ESLint rule that helps identify code that breaks the [Rules of React](/reference/rules). The linter does not require the compiler to be installed, so there's no risk in upgrading eslint-plugin-react-hooks. We recommend everyone upgrade today. + +If you have already installed `eslint-plugin-react-compiler`, you can now remove it and use `eslint-plugin-react-hooks@latest`. Many thanks to [@michaelfaith](https://bsky.app/profile/michael.faith) for contributing to this improvement! + +To install: + +npm +<TerminalBlock> +npm install --save-dev eslint-plugin-react-hooks@latest +</TerminalBlock> + +pnpm +<TerminalBlock> +pnpm add --save-dev eslint-plugin-react-hooks@latest +</TerminalBlock> + +yarn +<TerminalBlock> +yarn add --dev eslint-plugin-react-hooks@latest +</TerminalBlock> + +```js {6} +// eslint.config.js (Flat Config) +import reactHooks from 'eslint-plugin-react-hooks'; +import { defineConfig } from 'eslint/config'; + +export default defineConfig([ + reactHooks.configs.flat.recommended, +]); +``` + +```js {3} +// eslintrc.json (Legacy Config) +{ + "extends": ["plugin:react-hooks/recommended"], + // ... +} +``` + +To enable React Compiler rules, we recommend using the `recommended` preset. You can also check out the [README](https://github.com/react/react/blob/main/packages/eslint-plugin-react-hooks/README.md) for more instructions. Here are a few examples we featured at React Conf: + +- Catching `setState` patterns that cause render loops with [`set-state-in-render`](/reference/eslint-plugin-react-hooks/lints/set-state-in-render). +- Flagging expensive work inside effects via [`set-state-in-effect`](/reference/eslint-plugin-react-hooks/lints/set-state-in-effect). +- Preventing unsafe ref access during render with [`refs`](/reference/eslint-plugin-react-hooks/lints/refs). + +## What should I do about useMemo, useCallback, and React.memo? {/*what-should-i-do-about-usememo-usecallback-and-reactmemo*/} +By default, React Compiler will memoize your code based on its analysis and heuristics. In most cases, this memoization will be as precise, or moreso, than what you may have written — and as noted above, the compiler can memoize even in cases where `useMemo`/`useCallback` cannot be used, such as after an early return. + +However, in some cases developers may need more control over memoization. The `useMemo` and `useCallback` hooks can continue to be used with React Compiler as an escape hatch to provide control over which values are memoized. A common use-case for this is if a memoized value is used as an effect dependency, in order to ensure that an effect does not fire repeatedly even when its dependencies do not meaningfully change. + +For new code, we recommend relying on the compiler for memoization and using `useMemo`/`useCallback` where needed to achieve precise control. + +For existing code, we recommend either leaving existing memoization in place (removing it can change compilation output) or carefully testing before removing the memoization. + +## New apps should use React Compiler {/*new-apps-should-use-react-compiler*/} +We have partnered with the Expo, Vite, and Next.js teams to add the compiler to the new app experience. + +[Expo SDK 54](https://docs.expo.dev/guides/react-compiler/) and up has the compiler enabled by default, so new apps will automatically be able to take advantage of the compiler from the start. + +<TerminalBlock> +npx create-expo-app@latest +</TerminalBlock> + +[Vite](https://vite.dev/guide/) and [Next.js](https://nextjs.org/docs/app/api-reference/cli/create-next-app) users can choose the compiler enabled templates in `create-vite` and `create-next-app`. + +<TerminalBlock> +npm create vite@latest +</TerminalBlock> + +<br /> + +<TerminalBlock> +npx create-next-app@latest +</TerminalBlock> + +## Adopt React Compiler incrementally {/*adopt-react-compiler-incrementally*/} +If you're maintaining an existing application, you can roll out the compiler at your own pace. We published a step-by-step [incremental adoption guide](/learn/react-compiler/incremental-adoption) that covers gating strategies, compatibility checks, and rollout tooling so you can enable the compiler with confidence. + +## swc support (experimental) {/*swc-support-experimental*/} +React Compiler can be installed across [several build tools](/learn/react-compiler#installation) such as Babel, Vite, and Rsbuild. + +In addition to those tools, we have been collaborating with Kang Dongyoon ([@kdy1dev](https://x.com/kdy1dev)) from the [swc](https://swc.rs/) team on adding additional support for React Compiler as an swc plugin. While this work isn't done, Next.js build performance should now be considerably faster when the [React Compiler is enabled in your Next.js app](https://nextjs.org/docs/app/api-reference/config/next-config-js/reactCompiler). + +We recommend using Next.js [15.3.1](https://github.com/vercel/next.js/releases/tag/v15.3.1) or greater to get the best build performance. + +Vite users can continue to use [vite-plugin-react](https://github.com/vitejs/vite-plugin-react) to enable the compiler, by adding it as a [Babel plugin](/learn/react-compiler/installation#vite). We are also working with the [oxc](https://oxc.rs/) team to [add support for the compiler](https://github.com/oxc-project/oxc/issues/10048). Once [rolldown](https://github.com/rolldown/rolldown) is officially released and supported in Vite and oxc support is added for React Compiler, we'll update the docs with information on how to migrate. + +## Upgrading React Compiler {/*upgrading-react-compiler*/} +React Compiler works best when the auto-memoization applied is strictly for performance. Future versions of the compiler may change how memoization is applied, for example it could become more granular and precise. + +However, because product code may sometimes break the [rules of React](/reference/rules) in ways that aren't always statically detectable in JavaScript, changing memoization can occasionally have unexpected results. For example, a previously memoized value might be used as a dependency for a `useEffect` somewhere in the component tree. Changing how or whether this value is memoized can cause over or under-firing of that `useEffect`. While we encourage [useEffect only for synchronization](/learn/synchronizing-with-effects), your codebase may have `useEffect`s that cover other use cases, such as effects that needs to only run in response to specific values changing. + +In other words, changing memoization may under rare circumstances cause unexpected behavior. For this reason, we recommend following the Rules of React and employing continuous end-to-end testing of your app so you can upgrade the compiler with confidence and identify any rules of React violations that might cause issues. + +If you don't have good test coverage, we recommend pinning the compiler to an exact version (eg `1.0.0`) rather than a SemVer range (eg `^1.0.0`). You can do this by passing the `--save-exact` (npm/pnpm) or `--exact` flags (yarn) when upgrading the compiler. You should then do any upgrades of the compiler manually, taking care to check that your app still works as expected. + +--- + +Thanks to [Jason Bonta](https://x.com/someextent), [Jimmy Lai](https://x.com/feedthejim), [Kang Dongyoon](https://x.com/kdy1dev) (@kdy1dev), and [Dan Abramov](https://bsky.app/profile/danabra.mov) for reviewing and editing this post. diff --git a/src/content/blog/2025/12/03/critical-security-vulnerability-in-react-server-components.md b/src/content/blog/2025/12/03/critical-security-vulnerability-in-react-server-components.md new file mode 100644 index 000000000..a669a2c4e --- /dev/null +++ b/src/content/blog/2025/12/03/critical-security-vulnerability-in-react-server-components.md @@ -0,0 +1,208 @@ +--- +title: "Critical Security Vulnerability in React Server Components" +author: The React Team +date: 2025/12/03 +description: There is an unauthenticated remote code execution vulnerability in React Server Components. A fix has been published in versions 19.0.1, 19.1.2, and 19.2.1. We recommend upgrading immediately. + +--- + +December 3, 2025 by [The React Team](/community/team) + +--- + +<Intro> + +There is an unauthenticated remote code execution vulnerability in React Server Components. + +We recommend upgrading immediately. + +</Intro> + +--- + +On November 29th, Lachlan Davidson reported a security vulnerability in React that allows unauthenticated remote code execution by exploiting a flaw in how React decodes payloads sent to React Server Function endpoints. + +Even if your app does not implement any React Server Function endpoints it may still be vulnerable if your app supports React Server Components. + +This vulnerability was disclosed as [CVE-2025-55182](https://www.cve.org/CVERecord?id=CVE-2025-55182) and is rated CVSS 10.0. + +The vulnerability is present in versions 19.0, 19.1.0, 19.1.1, and 19.2.0 of: + +* [react-server-dom-webpack](https://www.npmjs.com/package/react-server-dom-webpack) +* [react-server-dom-parcel](https://www.npmjs.com/package/react-server-dom-parcel) +* [react-server-dom-turbopack](https://www.npmjs.com/package/react-server-dom-turbopack?activeTab=readme) + +## Immediate Action Required {/*immediate-action-required*/} + +A fix was introduced in versions [19.0.1](https://github.com/react/react/releases/tag/v19.0.1), [19.1.2](https://github.com/react/react/releases/tag/v19.1.2), and [19.2.1](https://github.com/react/react/releases/tag/v19.2.1). If you are using any of the above packages please upgrade to any of the fixed versions immediately. + +If your app’s React code does not use a server, your app is not affected by this vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability. + +### Affected frameworks and bundlers {/*affected-frameworks-and-bundlers*/} + +Some React frameworks and bundlers depended on, had peer dependencies for, or included the vulnerable React packages. The following React frameworks & bundlers are affected: [next](https://www.npmjs.com/package/next), [react-router](https://www.npmjs.com/package/react-router), [waku](https://www.npmjs.com/package/waku), [@parcel/rsc](https://www.npmjs.com/package/@parcel/rsc), [@vitejs/plugin-rsc](https://www.npmjs.com/package/@vitejs/plugin-rsc), and [rwsdk](https://www.npmjs.com/package/rwsdk). + +See the [update instructions below](#update-instructions) for how to upgrade to these patches. + +### Hosting Provider Mitigations {/*hosting-provider-mitigations*/} + +We have worked with a number of hosting providers to apply temporary mitigations. + +You should not depend on these to secure your app, and still update immediately. + +### Vulnerability overview {/*vulnerability-overview*/} + +[React Server Functions](https://react.dev/reference/rsc/server-functions) allow a client to call a function on a server. React provides integration points and tools that frameworks and bundlers use to help React code run on both the client and the server. React translates requests on the client into HTTP requests which are forwarded to a server. On the server, React translates the HTTP request into a function call and returns the needed data to the client. + +An unauthenticated attacker could craft a malicious HTTP request to any Server Function endpoint that, when deserialized by React, achieves remote code execution on the server. Further details of the vulnerability will be provided after the rollout of the fix is complete. + +## Update Instructions {/*update-instructions*/} + +<Note> + +These instructions have been updated to include the new vulnerabilities: + +- **Denial of Service - High Severity**: [CVE-2025-55184](https://www.cve.org/CVERecord?id=CVE-2025-55184) and [CVE-2025-67779](https://www.cve.org/CVERecord?id=CVE-2025-67779) (CVSS 7.5) +- **Source Code Exposure - Medium Severity**: [CVE-2025-55183](https://www.cve.org/CVERecord?id=CVE-2025-55183) (CVSS 5.3) +- **Denial of Service - High Severity**: January 26, 2026 [CVE-2026-23864](https://www.cve.org/CVERecord?id=CVE-2026-23864) (CVSS 7.5) + +See the [follow-up blog post](/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components) for more info. + +----- + +_Updated January 26, 2026._ +</Note> + +### Next.js {/*update-next-js*/} + +All users should upgrade to the latest patched version in their release line: + +```bash +npm install next@14.2.35 // for 13.3.x, 13.4.x, 13.5.x, 14.x +npm install next@15.0.8 // for 15.0.x +npm install next@15.1.12 // for 15.1.x +npm install next@15.2.9 // for 15.2.x +npm install next@15.3.9 // for 15.3.x +npm install next@15.4.11 // for 15.4.x +npm install next@15.5.10 // for 15.5.x +npm install next@16.0.11 // for 16.0.x +npm install next@16.1.5 // for 16.1.x + +npm install next@15.6.0-canary.60 // for 15.x canary releases +npm install next@16.1.0-canary.19 // for 16.x canary releases +``` + +15.0.8, 15.1.12, 15.2.9, 15.3.9, 15.4.10, 15.5.10, 15.6.0-canary.61, 16.0.11, 16.1.5 + +If you are on version `13.3` or later version of Next.js 13 (`13.3.x`, `13.4.x`, or `13.5.x`) please upgrade to version `14.2.35`. + +If you are on `next@14.3.0-canary.77` or a later canary release, downgrade to the latest stable 14.x release: + +```bash +npm install next@14 +``` + +See the [Next.js blog](https://nextjs.org/blog/security-update-2025-12-11) for the latest update instructions and the [previous changelog](https://nextjs.org/blog/CVE-2025-66478) for more info. + +### React Router {/*update-react-router*/} + +If you are using React Router's unstable RSC APIs, you should upgrade the following package.json dependencies if they exist: + +```bash +npm install react@latest +npm install react-dom@latest +npm install react-server-dom-parcel@latest +npm install react-server-dom-webpack@latest +npm install @vitejs/plugin-rsc@latest +``` + +### Expo {/*expo*/} + +To learn more about mitigating, read the article on [expo.dev/changelog](https://expo.dev/changelog/mitigating-critical-security-vulnerability-in-react-server-components). + +### Redwood SDK {/*update-redwood-sdk*/} + +Ensure you are on rwsdk>=1.0.0-alpha.0 + +For the latest beta version: + +```bash +npm install rwsdk@latest +``` + +Upgrade to the latest `react-server-dom-webpack`: + +```bash +npm install react@latest react-dom@latest react-server-dom-webpack@latest +``` + +See [Redwood docs](https://docs.rwsdk.com/migrating/) for more migration instructions. + +### Waku {/*update-waku*/} + +Upgrade to the latest `react-server-dom-webpack`: + +```bash +npm install react@latest react-dom@latest react-server-dom-webpack@latest waku@latest +``` + +See [Waku announcement](https://github.com/wakujs/waku/discussions/1823) for more migration instructions. + +### `@vitejs/plugin-rsc` {/*vitejs-plugin-rsc*/} + +Upgrade to the latest RSC plugin: + +```bash +npm install react@latest react-dom@latest @vitejs/plugin-rsc@latest +``` + +### `react-server-dom-parcel` {/*update-react-server-dom-parcel*/} + +Update to the latest version: + + ```bash + npm install react@latest react-dom@latest react-server-dom-parcel@latest + ``` + +### `react-server-dom-turbopack` {/*update-react-server-dom-turbopack*/} + +Update to the latest version: + + ```bash + npm install react@latest react-dom@latest react-server-dom-turbopack@latest + ``` + +### `react-server-dom-webpack` {/*update-react-server-dom-webpack*/} + +Update to the latest version: + + ```bash +npm install react@latest react-dom@latest react-server-dom-webpack@latest + ``` + + +### React Native {/*react-native*/} + +For React Native users not using a monorepo or `react-dom`, your `react` version should be pinned in your `package.json`, and there are no additional steps needed. + +If you are using React Native in a monorepo, you should update _only_ the impacted packages if they are installed: + +- `react-server-dom-webpack` +- `react-server-dom-parcel` +- `react-server-dom-turbopack` + +This is required to mitigate the security advisory, but you do not need to update `react` and `react-dom` so this will not cause the version mismatch error in React Native. + +See [this issue](https://github.com/react/react-native/issues/54772#issuecomment-3617929832) for more information. + + +## Timeline {/*timeline*/} + +* **November 29th**: Lachlan Davidson reported the security vulnerability via [Meta Bug Bounty](https://bugbounty.meta.com/). +* **November 30th**: Meta security researchers confirmed and began working with the React team on a fix. +* **December 1st**: A fix was created and the React team began working with affected hosting providers and open source projects to validate the fix, implement mitigations and roll out the fix +* **December 3rd**: The fix was published to npm and the publicly disclosed as CVE-2025-55182. + +## Attribution {/*attribution*/} + +Thank you to [Lachlan Davidson](https://github.com/lachlan2k) for discovering, reporting, and working to help fix this vulnerability. diff --git a/src/content/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components.md b/src/content/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components.md index 70e5c2e65..206d49e39 100644 --- a/src/content/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components.md +++ b/src/content/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components.md @@ -98,7 +98,7 @@ If you are using React Native in a monorepo, you should update _only_ the impact This is required to mitigate the security advisories, but you do not need to update `react` and `react-dom` so this will not cause the version mismatch error in React Native. -See [this issue](https://github.com/facebook/react-native/issues/54772#issuecomment-3617929832) for more information. +See [this issue](https://github.com/react/react-native/issues/54772#issuecomment-3617929832) for more information. --- diff --git a/src/content/blog/index.md b/src/content/blog/index.md index fc8a2969b..69723119a 100644 --- a/src/content/blog/index.md +++ b/src/content/blog/index.md @@ -64,7 +64,7 @@ The React team is excited to share a few updates: ### All release notes {/*all-release-notes*/} -Not every React release deserves its own blog post, but you can find a detailed changelog for every release in the [`CHANGELOG.md`](https://github.com/facebook/react/blob/main/CHANGELOG.md) file in the React repository, as well as on the [Releases](https://github.com/facebook/react/releases) page. +Not every React release deserves its own blog post, but you can find a detailed changelog for every release in the [`CHANGELOG.md`](https://github.com/react/react/blob/main/CHANGELOG.md) file in the React repository, as well as on the [Releases](https://github.com/react/react/releases) page. --- diff --git a/src/content/community/acknowledgements.md b/src/content/community/acknowledgements.md index c87a92979..e176d0fc8 100644 --- a/src/content/community/acknowledgements.md +++ b/src/content/community/acknowledgements.md @@ -4,7 +4,11 @@ title: Acknowledgements <Intro> +<<<<<<< HEAD React was originally created by [Jordan Walke.](https://github.com/jordwalke) Today, React has a [dedicated full-time team working on it](/community/team), as well as over a thousand [open source contributors.](https://github.com/facebook/react/blob/main/AUTHORS) +======= +React was originally created by [Jordan Walke.](https://github.com/jordwalke) Today, React has a [dedicated full-time team working on it](/community/team), as well as over a thousand [open source contributors.](https://github.com/react/react/graphs/contributors) +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca </Intro> diff --git a/src/content/community/conferences.md b/src/content/community/conferences.md index cbdd70f7e..fd4b4e129 100644 --- a/src/content/community/conferences.md +++ b/src/content/community/conferences.md @@ -10,6 +10,192 @@ Do you know of a local React.js conference? Add it here! (Please keep the list c ## Upcoming Conferences {/*upcoming-conferences*/} +<<<<<<< HEAD +======= +### React Paris 2026 {/*react-paris-2026*/} +March 26 - 27, 2026. In-person in Paris, France (hybrid event) + +[Website](https://react.paris/) - [Twitter](https://x.com/BeJS_) + +### CityJS London 2026 {/*cityjs-london-2026*/} +April 14-17, 2026. In-person in London + +[Website](https://india.cityjsconf.org/) - [Twitter](https://x.com/cityjsconf) - [Bluesky](https://bsky.app/profile/cityjsconf.bsky.social) + +### ZurichJS Conf 2026 {/*zurichjs-conf-2026*/} +September 10-11, 2026. In-person in Zurich, Switzerland + +[Website](https://conf.zurichjs.com?utm_campaign=ZurichJS_Conf&utm_source=referral&utm_content=reactjs_community_conferences) - [Twitter](https://x.com/zurichjs) - [LinkedIn](https://www.linkedin.com/company/zurichjs/) + +### React Conf Japan 2027 {/*react-conf-japan-2027*/} +April 24, 2027. In-person in Tokyo, Japan + +[Website](https://reactconf.jp/) - [Twitter](https://x.com/reactconfjp) + +## Past Conferences {/*past-conferences*/} + +### CityJS New Delhi 2026 {/*cityjs-newdelhi-2026*/} +February 12-13, 2026. In-person in New Delhi, India + +[Website](https://india.cityjsconf.org/) - [Twitter](https://x.com/cityjsconf) - [Bluesky](https://bsky.app/profile/cityjsconf.bsky.social) + +### CityJS Singapore 2026 {/*cityjs-singapore-2026*/} +February 4-6, 2026. In-person in Singapore + +[Website](https://india.cityjsconf.org/) - [Twitter](https://x.com/cityjsconf) - [Bluesky](https://bsky.app/profile/cityjsconf.bsky.social) + +### React Advanced London 2025 {/*react-advanced-london-2025*/} +November 28 & December 1, 2025. In-person in London, UK + online (hybrid event) + +[Website](https://reactadvanced.com/) - [Twitter](https://x.com/reactadvanced) + +### React Summit US 2025 {/*react-summit-us-2025*/} +November 18 - 21, 2025. In-person in New York, USA + remote (hybrid event) + +[Website](https://reactsummit.us/) - [Twitter](https://x.com/reactsummit) + +### React India 2025 {/*react-india-2025*/} +October 31 - November 01, 2025. In-person in Goa, India (hybrid event) + Oct 15 2025 - remote day + +[Website](https://www.reactindia.io) - [Twitter](https://twitter.com/react_india) - [Facebook](https://www.facebook.com/ReactJSIndia) - [Youtube](https://www.youtube.com/channel/UCaFbHCBkPvVv1bWs_jwYt3w) + +### React Conf 2025 {/*react-conf-2025*/} +October 7-8, 2025. Henderson, Nevada, USA and free livestream + +[Website](https://conf.react.dev/) - [Twitter](https://x.com/reactjs) - [Bluesky](https://bsky.app/profile/react.dev) + +### RenderCon Kenya 2025 {/*rendercon-kenya-2025*/} +October 04, 2025. Nairobi, Kenya + +[Website](https://rendercon.org/) - [Twitter](https://twitter.com/renderconke) - [LinkedIn](https://www.linkedin.com/company/renderconke/) - [YouTube](https://www.youtube.com/channel/UC0bCcG8gHUL4njDOpQGcMIA) + +### React Alicante 2025 {/*react-alicante-2025*/} +October 2-4, 2025. Alicante, Spain. + +[Website](https://reactalicante.es/) - [Twitter](https://x.com/ReactAlicante) - [Bluesky](https://bsky.app/profile/reactalicante.es) - [YouTube](https://www.youtube.com/channel/UCaSdUaITU1Cz6PvC97A7e0w) + +### React Universe Conf 2025 {/*react-universe-conf-2025*/} +September 2-4, 2025. Wrocław, Poland. + +[Website](https://www.reactuniverseconf.com/) - [Twitter](https://twitter.com/react_native_eu) - [LinkedIn](https://www.linkedin.com/events/reactuniverseconf7163919537074118657/) + +### React Nexus 2025 {/*react-nexus-2025*/} +July 03 - 05, 2025. In-person in Bangalore, India + +[Website](https://reactnexus.com/) - [Twitter](https://x.com/ReactNexus) - [Bluesky](https://bsky.app/profile/reactnexus.com) - [Linkedin](https://www.linkedin.com/company/react-nexus) - [YouTube](https://www.youtube.com/reactify_in) + +### React Summit 2025 {/*react-summit-2025*/} +June 13 - 17, 2025. In-person in Amsterdam, Netherlands + remote (hybrid event) + +[Website](https://reactsummit.com/) - [Twitter](https://x.com/reactsummit) + +### React Norway 2025 {/*react-norway-2025*/} +June 13, 2025. In-person in Oslo, Norway + remote (virtual event) + +[Website](https://reactnorway.com/) - [Twitter](https://x.com/ReactNorway) + +### CityJS Athens 2025 {/*cityjs-athens*/} +May 27 - 31, 2025. In-person in Athens, Greece + +[Website](https://athens.cityjsconf.org/) - [Twitter](https://x.com/cityjsconf) - [Bluesky](https://bsky.app/profile/cityjsconf.bsky.social) + +### App.js Conf 2025 {/*appjs-conf-2025*/} +May 28 - 30, 2025. In-person in Kraków, Poland + remote + +[Website](https://appjs.co) - [Twitter](https://twitter.com/appjsconf) + +### CityJS London 2025 {/*cityjs-london*/} +April 23 - 25, 2025. In-person in London, UK + +[Website](https://london.cityjsconf.org/) - [Twitter](https://x.com/cityjsconf) - [Bluesky](https://bsky.app/profile/cityjsconf.bsky.social) + +### React Paris 2025 {/*react-paris-2025*/} +March 20 - 21, 2025. In-person in Paris, France (hybrid event) + +[Website](https://react.paris/) - [Twitter](https://x.com/BeJS_) - [YouTube](https://www.youtube.com/playlist?list=PL53Z0yyYnpWitP8Zv01TSEQmKLvuRh_Dj) + +### React Native Connection 2025 {/*react-native-connection-2025*/} +April 3 (Reanimated Training) + April 4 (Conference), 2025. Paris, France. + +[Website](https://reactnativeconnection.io/) - [X](https://x.com/reactnativeconn) - [Bluesky](https://bsky.app/profile/reactnativeconnect.bsky.social) + +### React Day Berlin 2024 {/*react-day-berlin-2024*/} +December 13 & 16, 2024. In-person in Berlin, Germany + remote (hybrid event) + +[Website](https://reactday.berlin/) - [Twitter](https://x.com/reactdayberlin) + +### React Africa 2024 {/*react-africa-2024*/} +November 29, 2024. In-person in Casablanca, Morocco (hybrid event) + +[Website](https://react-africa.com/) - [Twitter](https://x.com/BeJS_) + +### React Summit US 2024 {/*react-summit-us-2024*/} +November 19 & 22, 2024. In-person in New York, USA + online (hybrid event) + +[Website](https://reactsummit.us/) - [Twitter](https://twitter.com/reactsummit) - [Videos](https://portal.gitnation.org/) + +### React Native London Conf 2024 {/*react-native-london-2024*/} +November 14 & 15, 2024. In-person in London, UK + +[Website](https://reactnativelondon.co.uk/) - [Twitter](https://x.com/RNLConf) + +### React Advanced London 2024 {/*react-advanced-london-2024*/} +October 25 & 28, 2024. In-person in London, UK + online (hybrid event) + +[Website](https://reactadvanced.com/) - [Twitter](https://x.com/reactadvanced) + +### reactjsday 2024 {/*reactjsday-2024*/} +October 25, 2024. In-person in Verona, Italy + online (hybrid event) + +[Website](https://2024.reactjsday.it/) - [Twitter](https://x.com/reactjsday) - [Facebook](https://www.facebook.com/GrUSP/) - [YouTube](https://www.youtube.com/c/grusp) + +### React Brussels 2024 {/*react-brussels-2024*/} +October 18, 2024. In-person in Brussels, Belgium (hybrid event) + +[Website](https://www.react.brussels/) - [Twitter](https://x.com/BrusselsReact) - [YouTube](https://www.youtube.com/playlist?list=PL53Z0yyYnpWimQ0U75woee2zNUIFsiDC3) + +### React India 2024 {/*react-india-2024*/} +October 17 - 19, 2024. In-person in Goa, India (hybrid event) + Oct 15 2024 - remote day + +[Website](https://www.reactindia.io) - [Twitter](https://twitter.com/react_india) - [Facebook](https://www.facebook.com/ReactJSIndia) - [Youtube](https://www.youtube.com/channel/UCaFbHCBkPvVv1bWs_jwYt3w) + +### RenderCon Kenya 2024 {/*rendercon-kenya-2024*/} +October 04 - 05, 2024. Nairobi, Kenya + +[Website](https://rendercon.org/) - [Twitter](https://twitter.com/renderconke) - [LinkedIn](https://www.linkedin.com/company/renderconke/) - [YouTube](https://www.youtube.com/channel/UC0bCcG8gHUL4njDOpQGcMIA) + +### React Alicante 2024 {/*react-alicante-2024*/} +September 19-21, 2024. Alicante, Spain. + +[Website](https://reactalicante.es/) - [Twitter](https://twitter.com/ReactAlicante) - [YouTube](https://www.youtube.com/channel/UCaSdUaITU1Cz6PvC97A7e0w) + +### React Universe Conf 2024 {/*react-universe-conf-2024*/} +September 5-6, 2024. Wrocław, Poland. + +[Website](https://www.reactuniverseconf.com/) - [Twitter](https://twitter.com/react_native_eu) - [LinkedIn](https://www.linkedin.com/events/reactuniverseconf7163919537074118657/) + + +### React Rally 2024 🐙 {/*react-rally-2024*/} +August 12-13, 2024. Park City, UT, USA + +[Website](https://reactrally.com) - [Twitter](https://twitter.com/ReactRally) - [YouTube](https://www.youtube.com/channel/UCXBhQ05nu3L1abBUGeQ0ahw) + +### The Geek Conf 2024 {/*the-geek-conf-2024*/} +July 25, 2024. In-person in Berlin, Germany + remote (hybrid event) + +[Website](https://thegeekconf.com) - [Twitter](https://twitter.com/thegeekconf) + +### Chain React 2024 {/*chain-react-2024*/} +July 17-19, 2024. In-person in Portland, OR, USA + +[Website](https://chainreactconf.com) - [Twitter](https://twitter.com/ChainReactConf) + +### React Nexus 2024 {/*react-nexus-2024*/} +July 04 & 05, 2024. Bangalore, India (In-person event) + +[Website](https://reactnexus.com/) - [Twitter](https://twitter.com/ReactNexus) - [Linkedin](https://www.linkedin.com/company/react-nexus) - [YouTube](https://www.youtube.com/reactify_in) + +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca ### React Summit 2024 {/*react-summit-2024*/} June 14 & 18, 2024. In-person in Amsterdam, Netherlands + remote (hybrid event) diff --git a/src/content/community/index.md b/src/content/community/index.md index 1e28a27f0..a48d44e22 100644 --- a/src/content/community/index.md +++ b/src/content/community/index.md @@ -10,7 +10,7 @@ React has a community of millions of developers. On this page we've listed some ## Code of Conduct {/*code-of-conduct*/} -Before participating in React's communities, [please read our Code of Conduct.](https://github.com/facebook/react/blob/main/CODE_OF_CONDUCT.md) We have adopted the [Contributor Covenant](https://www.contributor-covenant.org/) and we expect that all community members adhere to the guidelines within. +Before participating in React's communities, [please read our Code of Conduct.](https://github.com/react/react/blob/main/CODE_OF_CONDUCT.md) We have adopted the [Contributor Covenant](https://www.contributor-covenant.org/) and we expect that all community members adhere to the guidelines within. ## Stack Overflow {/*stack-overflow*/} diff --git a/src/content/community/team.md b/src/content/community/team.md index 0c6c63a8b..26f776a24 100644 --- a/src/content/community/team.md +++ b/src/content/community/team.md @@ -4,20 +4,19 @@ title: "Meet the Team" <Intro> -React development is led by a dedicated team working full time at Meta. It also receives contributions from people all over the world. +React development is led by contributors from companies and communities all over the world. </Intro> -## React Core {/*react-core*/} +React work is organized into working groups, each responsible for an area of the project such as Server, DOM, Fiber, Docs & Community, Compiler, DevX, and React Native. Each working group is represented on the React Leadership Council, which coordinates direction across the project. -The React Core team members work full time on the core component APIs, the engine that powers React DOM and React Native, React DevTools, and the React documentation website. +## Leadership Council {/*leadership-council*/} -Current members of the React team are listed in alphabetical order below. - -<TeamMember name="Andrew Clark" permalink="andrew-clark" photo="/images/team/acdlite.jpg" github="acdlite" twitter="acdlite" threads="acdlite" title="Engineer at Vercel"> +<TeamMember name="Andrew Clark" permalink="andrew-clark" photo="/images/team/acdlite.jpg" github="acdlite" twitter="acdlite" threads="acdlite" title="Engineer at Vercel" group="Fiber*, DOM"> Andrew got started with web development by making sites with WordPress, and eventually tricked himself into doing JavaScript. His favorite pastime is karaoke. Andrew is either a Disney villain or a Disney princess, depending on the day. </TeamMember> +<<<<<<< HEAD <TeamMember name="Andrey Lunyov" permalink="andrey-lunyov" photo="/images/team/andrey-lunyov.jpg" github="alunyov" twitter="alunyov" threads="alunyov" title="Engineer at Meta"> Andrey started his career as a designer and then gradually transitioned into web development. After joining the React Data team at Meta he worked on adding an incremental JavaScript compiler to Relay, and then later on, worked on removing the same compiler from Relay. Outside of work, Andrey likes to play music and engage in various sports. </TeamMember> @@ -27,6 +26,99 @@ Current members of the React team are listed in alphabetical order below. </TeamMember> <TeamMember name="Eli White" permalink="eli-white" photo="/images/team/eli-white.jpg" github="TheSavior" twitter="Eli_White" threads="elicwhite" title="Engineering Manager at Meta"> +======= +<TeamMember name="Jack Pope" permalink="jack-pope" photo="/images/team/jack-pope.jpg" github="jackpope" personal="jackpope.me" title="Engineer at Meta" group="DOM*, Fiber"> + Shortly after being introduced to AutoHotkey, Jack had written scripts to automate everything he could think of. When reaching limitations there, he dove headfirst into web app development and hasn't looked back. Most recently, Jack worked on the web platform at Instagram before moving to React. His favorite programming language is JSX. +</TeamMember> + +<TeamMember name="Mofei Zhang" permalink="mofei-zhang" photo="/images/team/mofei-zhang.png" github="mofeiZ" threads="z_mofei" title="Engineer at Meta" group="Compiler*"> + Mofei started programming when she realized it can help her cheat in video games. She focused on operating systems in undergrad / grad school, but now finds herself happily tinkering on React. Outside of work, she enjoys debugging bouldering problems and planning her next backpacking trip(s). +</TeamMember> + +<TeamMember name="Moti Zilberman" permalink="moti-zilberman" photo="/images/team/gh-motiz88.jpg" github="motiz88" title="Engineer at Meta" group="DevX*" /> + +<TeamMember name="Nicola Corti" permalink="nicola-corti" photo="/images/team/gh-cortinico.jpg" github="cortinico" title="Engineer at Meta" group="React Native*, Docs & Community" /> + +<TeamMember name="Rick Hanlon" permalink="rick-hanlon" photo="/images/team/rickhanlonii.jpg" github="rickhanlonii" twitter="rickyfm" threads="rickhanlonii" bsky="ricky.fm" title="Engineer at Meta" group="Docs & Community*, DOM, Fiber, Server, DevX"> + Ricky majored in theoretical math and somehow found himself on the React Native team for a couple years before joining the React team. When he's not programming you can find him snowboarding, biking, climbing, golfing, or closing GitHub issues that do not match the issue template. +</TeamMember> + +<TeamMember name="Sebastian Silbermann" permalink="sebastian-silbermann" photo="/images/team/sebsilbermann.jpg" github="eps1lon" twitter="sebsilbermann" threads="sebsilbermann" title="Engineer at Vercel" group="Server*, DOM, Fiber, DevX"> + Sebastian learned programming to make the browser games he played during class more enjoyable. Eventually this lead to contributing to as much open source code as possible. Outside of coding he's busy making sure people don't confuse him with the other Sebastians and Zilberman of the React community. +</TeamMember> + +## Working Group members {/*working-group-members*/} + +<TeamMember name="Alex Hunt" permalink="alex-hunt" photo="/images/team/gh-huntie.jpg" github="huntie" title="Engineer at Meta" group="DevX, React Native" /> + +<TeamMember name="Aurora Scharff" permalink="aurora-scharff" photo="/images/team/gh-aurorascharff.jpg" github="aurorascharff" title="Engineer at Vercel" group="Docs & Community" /> + +<TeamMember name="Brent Vatne" permalink="brent-vatne" photo="/images/team/gh-brentvatne.jpg" github="brentvatne" title="Engineer at Expo" group="React Native" /> + +<TeamMember name="Dan Abramov" permalink="dan-abramov" photo="/images/team/gaearon.jpg" github="gaearon" bsky="danabra.mov" title="Engineer at Vercel" group="Docs & Community"> + Dan got into programming after he accidentally discovered Visual Basic inside Microsoft PowerPoint. He has found his true calling in turning [Sebastian](#sebastian-markbåge)'s tweets into long-form blog posts. Dan occasionally wins at Fortnite by hiding in a bush until the game ends. +</TeamMember> + +<TeamMember name="Hendrik Liebau" permalink="hendrik-liebau" photo="/images/team/hendrik.jpg" github="unstubbable" bsky="unstubbable.bsky.social" twitter="unstubbable" title="Engineer at Vercel" group="Server"> + Hendrik’s journey in tech started in the late 90s when he built his first websites with Netscape Communicator. After earning a diploma in computer science and working at digital agencies, he built a React Server Components bundler and library, paving the way to his role on the Next.js team. Outside of work, he enjoys cycling and tinkering in his workshop. +</TeamMember> + +<TeamMember name="Jordan Eldredge" permalink="jordan-eldredge" photo="/images/team/gh-captbaritone.jpg" github="captbaritone" title="Engineer at Meta" group="Server" /> + +<TeamMember name="Josh Story" permalink="josh-story" photo="/images/team/josh.jpg" github="gnoff" bsky="storyhb.com" title="Engineer at Vercel" group="DOM, Fiber, Server"> + Josh majored in Mathematics and discovered programming while in college. His first professional developer job was to program insurance rate calculations in Microsoft Excel, the paragon of Reactive Programming which must be why he now works on React. In between that time Josh has been an IC, Manager, and Executive at a few startups. outside of work he likes to push his limits with cooking. +</TeamMember> + +<TeamMember name="Kevin Gozali" permalink="kevin-gozali" photo="/images/team/gh-fkgozali.jpg" github="fkgozali" title="Engineer at Meta" group="React Native" /> + +<TeamMember name="Khalef Hosany" permalink="khalef-hosany" photo="/images/team/gh-khalef1.jpg" github="Khalef1" title="Engineer at Microsoft" group="React Native" /> + +<TeamMember name="Krzysztof Magiera" permalink="krzysztof-magiera" photo="/images/team/gh-kmagiera.jpg" github="kmagiera" title="Engineer at Software Mansion" group="React Native" /> + +<TeamMember name="Lauren Tan" permalink="lauren-tan" photo="/images/team/lauren.jpg" github="poteto" twitter="potetotes" threads="potetotes" bsky="no.lol" title="Engineer at Cursor" group="Compiler"> + Lauren's programming career peaked when she first discovered the `<marquee>` tag. She’s been chasing that high ever since. She studied Finance instead of CS in college, so she learned to code using Excel. Lauren enjoys dropping cheeky memes in chat, playing video games with her partner, learning Korean, and petting her dog Zelda. +</TeamMember> + +<TeamMember name="Matt Carroll" permalink="matt-carroll" photo="/images/team/matt-carroll.png" github="mattcarrollcode" twitter="mattcarrollcode" threads="mattcarrollcode" title="Developer Advocate at Meta" group="Docs & Community"> + Matt stumbled into coding, and since then, has become enamored with creating things in communities that can’t be created alone. Prior to React, he worked on YouTube, the Google Assistant, Fuchsia, and Google Cloud AI and Evernote. When he's not trying to make better developer tools he enjoys the mountains, jazz, and spending time with his family. +</TeamMember> + +<TeamMember name="Michael Leon" permalink="michael-leon" photo="/images/team/gh-fbmal7.jpg" github="fbmal7" title="Engineer at Meta" group="DevX" /> + +<TeamMember name="Michał Pierzchała" permalink="michal-pierzchala" photo="/images/team/gh-thymikee.jpg" github="thymikee" title="Engineer at Callstack" group="React Native" /> + +<TeamMember name="Mike Vitousek" permalink="mike-vitousek" photo="/images/team/mike.jpg" github="mvitousek" title="Engineer at Meta" group="Compiler"> + Mike went to grad school dreaming of becoming a professor but realized that he liked building things a lot more than writing grant applications. Mike joined Meta to work on Javascript infrastructure, which ultimately led him to work on the React Compiler. When not hacking on either Javascript or OCaml, Mike can often be found hiking or skiing in the Pacific Northwest. +</TeamMember> + +<TeamMember name="Pieter De Baets" permalink="pieter-de-baets" photo="/images/team/gh-javache.jpg" github="javache" title="Engineer at Meta" group="Compiler, Fiber, React Native" /> + +<TeamMember name="Riccardo Cipolleschi" permalink="riccardo-cipolleschi" photo="/images/team/gh-cipolleschi.png" github="cipolleschi" title="Engineer at Meta" group="Docs & Community, React Native" /> + +<TeamMember name="Rob Hogan" permalink="rob-hogan" photo="/images/team/gh-rh389.jpg" github="rh389" title="Engineer at Meta" group="DevX" /> + +<TeamMember name="Rubén Norte" permalink="ruben-norte" photo="/images/team/gh-rubennorte.jpg" github="rubennorte" title="Engineer at Meta" group="Fiber" /> + +<TeamMember name="Ruslan Lesiutin" permalink="ruslan-lesiutin" photo="/images/team/lesiutin.jpg" github="hoxyq" twitter="ruslanlesiutin" threads="lesiutin" title="Engineer at Meta" group="DOM, DevX"> + Ruslan's introduction to UI programming started when he was a kid by manually editing HTML templates for his custom gaming forums. Somehow, he ended up majoring in Computer Science. He enjoys music, games, and memes. Mostly memes. +</TeamMember> + +<TeamMember name="Sam Selikoff" permalink="sam-selikoff" photo="/images/team/gh-samselikoff.jpg" github="samselikoff" title="Engineer at Vercel" group="Docs & Community" /> + +<TeamMember name="Sophie Alpert" permalink="sophie-alpert" photo="/images/team/sophiebits.jpg" github="sophiebits" twitter="sophiebits" threads="sophiebits" personal="sophiebits.com" title="Independent Engineer" group="Docs & Community, DOM, Fiber"> + Four days after React was released, Sophie rewrote the entirety of her then-current project to use it, which she now realizes was perhaps a bit reckless. After she became the project's #1 committer, she wondered why she wasn't getting paid by Facebook like everyone else was and joined the team officially to lead React through its adolescent years. Though she quit that job years ago, somehow she's still in the team's group chats and “providing value”. +</TeamMember> + +<TeamMember name="Steven Moyes" permalink="steven-moyes" photo="/images/team/gh-stmoy.jpg" github="stmoy" title="Engineer at Amazon" group="React Native" /> + +<TeamMember name="Vitali Zaidman" permalink="vitali-zaidman" photo="/images/team/gh-vzaidman.jpg" github="vzaidman" title="Engineer at Meta" group="DevX" /> + +<TeamMember name="Vojtěch Šimek" permalink="vojtech-simek" photo="/images/team/gh-simek.png" github="simek" title="Developer" group="Docs & Community" /> + +## Advisors {/*advisors*/} + +<TeamMember name="Eli White" permalink="eli-white" photo="/images/team/eli-white.jpg" github="elicwhite" twitter="Eli_White" threads="elicwhite" title="Engineer at Meta"> +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca Eli got into programming after he got suspended from middle school for hacking. He has been working on React and React Native since 2017. He enjoys eating treats, especially ice cream and apple pie. You can find Eli trying quirky activities like parkour, indoor skydiving, and aerial silks. </TeamMember> @@ -34,10 +126,21 @@ Current members of the React team are listed in alphabetical order below. Jason likes having large volumes of Amazon packages delivered to the office so that he can build forts. Despite literally walling himself off from his team at times and not understanding how for-of loops work, we appreciate him for the unique qualities he brings to his work. </TeamMember> +<TeamMember name="Jimmy Lai" permalink="jimmy-lai" photo="/images/team/jimmy-lai.jpg" github="feedthejim" title="Engineering Director, Next.js at Vercel"> + Like many others, Jimmy started programming with the hopes of being able to work in the gaming industry. Fast forward a few years, he somehow decided that React and Javascript were pretty fun and that helping other developers build fast experiences was a more interesting life goal. After starting his career at Meta, working on product infrastructure and (briefly) on React Native, Jimmy now works at Vercel, where he helps his team build Next.js. He sadly does not get much time for video games anymore. +</TeamMember> + +<TeamMember name="Seth Webster" permalink="seth-webster" photo="/images/team/seth.jpg" github="sethwebster" twitter="sethwebster" threads="sethwebster" personal="sethwebster.com" title="Executive Director, React Foundation, Chief Developer Evangelist at Expo"> + Seth started programming as a kid growing up in Tucson, AZ. After school, he was bitten by the music bug and was a touring musician for about 10 years before returning to *work*, starting with Intuit. In his spare time, he loves [taking pictures](https://www.sethwebster.com) and flying for animal rescues in the northeastern United States. +</TeamMember> + +## Emeritus {/*emeritus*/} + <TeamMember name="Joe Savona" permalink="joe-savona" photo="/images/team/joe.jpg" github="josephsavona" twitter="en_JS" threads="joesavona" title="Engineer at Meta"> Joe was planning to major in math and philosophy but got into computer science after writing physics simulations in Matlab. Prior to React, he worked on Relay, RSocket.js, and the Skip programming language. While he’s not building some sort of reactive system he enjoys running, studying Japanese, and spending time with his family. </TeamMember> +<<<<<<< HEAD <TeamMember name="Josh Story" permalink="josh-story" photo="/images/team/josh.jpg" github="gnoff" twitter="joshcstory" title="Engineer at Vercel"> Josh majored in Mathematics and discovered programming while in college. His first professional developer job was to program insurance rate calculations in Microsoft Excel, the paragon of Reactive Programming which must be why he now works on React. In between that time Josh has been an IC, Manager, and Executive at a few startups. outside of work he likes to push his limits with cooking. </TeamMember> @@ -70,10 +173,21 @@ Current members of the React team are listed in alphabetical order below. Sathya hated the Dragon Book in school but somehow ended up working on compilers all his career. When he's not compiling React components, he's either drinking coffee or eating yet another Dosa. </TeamMember> +======= +<TeamMember name="Jordan Brown" permalink="jordan-brown" photo="/images/team/jordan.jpg" github="jbrown215" title="Engineer at Meta"> + Jordan started coding by building iPhone apps, where he was pushing and popping view controllers before he knew that for-loops were a thing. He enjoys working on technology that developers love, which naturally drew him to React. Outside of work he enjoys reading, kiteboarding, and playing guitar. +</TeamMember> + +<TeamMember name="Pieter Vanderwerff" permalink="pieter-vanderwerff" photo="/images/team/pieter.jpg" github="pieterv" threads="pietervanderwerff" title="Engineer at Meta"> + Pieter studied building science but after failing to get a job he made himself a website and things escalated from there. At Meta, he enjoys working on performance, languages and now React. When he's not programming you can find him off-road in the mountains. +</TeamMember> + +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca <TeamMember name="Sebastian Markbåge" permalink="sebastian-markbåge" photo="/images/team/sebmarkbage.jpg" github="sebmarkbage" twitter="sebmarkbage" threads="sebmarkbage" title="Engineer at Vercel"> Sebastian majored in psychology. He's usually quiet. Even when he says something, it often doesn't make sense to the rest of us until a few months later. The correct way to pronounce his surname is "mark-boa-geh" but he settled for "mark-beige" out of pragmatism -- and that's how he approaches React. </TeamMember> +<<<<<<< HEAD <TeamMember name="Sebastian Silbermann" permalink="sebastian-silbermann" photo="/images/team/sebsilbermann.jpg" github="eps1lon" twitter="sebsilbermann" threads="sebsilbermann" title="Independent Engineer"> Sebastian learned programming to make the browser games he played during class more enjoyable. Eventually this lead to contributing to as much open source code as possible. Outside of coding he's busy making sure people don't confuse him with the other Sebastians and Zilberman of the React community. </TeamMember> @@ -90,10 +204,10 @@ Current members of the React team are listed in alphabetical order below. Tianyu’s interest in computers started as a kid because he loves video games. So he majored in computer science and still plays childish games like League of Legends. When he is not in front of a computer, he enjoys playing with his two kittens, hiking and kayaking. </TeamMember> +======= +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca <TeamMember name="Yuzhi Zheng" permalink="yuzhi-zheng" photo="/images/team/yuzhi.jpg" github="yuzhi" twitter="yuzhiz" threads="yuzhiz" title="Engineering Manager at Meta"> Yuzhi studied Computer Science in school. She liked the instant gratification of seeing code come to life without having to physically be in a laboratory. Now she’s a manager in the React org. Before management, she used to work on the Relay data fetching framework. In her spare time, Yuzhi enjoys optimizing her life via gardening and home improvement projects. </TeamMember> -## Past contributors {/*past-contributors*/} - You can find the past team members and other people who significantly contributed to React over the years on the [acknowledgements](/community/acknowledgements) page. diff --git a/src/content/community/versioning-policy.md b/src/content/community/versioning-policy.md index fad926c57..49a1fd434 100644 --- a/src/content/community/versioning-policy.md +++ b/src/content/community/versioning-policy.md @@ -132,7 +132,7 @@ If you're the author of a third party React framework, library, developer tool, ``` - Run your test suite against the updated packages. - If everything passes, great! You can expect that your project will work with the next minor React release. -- If something breaks unexpectedly, please let us know by [filing an issue](https://github.com/facebook/react/issues). +- If something breaks unexpectedly, please let us know by [filing an issue](https://github.com/react/react/issues). A project that uses this workflow is Next.js. You can refer to their [CircleCI configuration](https://github.com/zeit/next.js/blob/c0a1c0f93966fe33edd93fb53e5fafb0dcd80a9e/.circleci/config.yml) as an example. @@ -162,4 +162,4 @@ If a feature is not documented, they may be accompanied by an [RFC](https://gith We will post to the [React blog](/blog) when we're ready to announce new experiments, but that doesn't mean we will publicize every experiment. -You can always refer to our public GitHub repository's [history](https://github.com/facebook/react/commits/main) for a comprehensive list of changes. +You can always refer to our public GitHub repository's [history](https://github.com/react/react/commits/main) for a comprehensive list of changes. diff --git a/src/content/learn/react-compiler/debugging.md b/src/content/learn/react-compiler/debugging.md new file mode 100644 index 000000000..a2981e094 --- /dev/null +++ b/src/content/learn/react-compiler/debugging.md @@ -0,0 +1,93 @@ +--- +title: Debugging and Troubleshooting +--- + +<Intro> +This guide helps you identify and fix issues when using React Compiler. Learn how to debug compilation problems and resolve common issues. +</Intro> + +<YouWillLearn> + +* The difference between compiler errors and runtime issues +* Common patterns that break compilation +* Step-by-step debugging workflow + +</YouWillLearn> + +## Understanding Compiler Behavior {/*understanding-compiler-behavior*/} + +React Compiler is designed to handle code that follows the [Rules of React](/reference/rules). When it encounters code that might break these rules, it safely skips optimization rather than risk changing your app's behavior. + +### Compiler Errors vs Runtime Issues {/*compiler-errors-vs-runtime-issues*/} + +**Compiler errors** occur at build time and prevent your code from compiling. These are rare because the compiler is designed to skip problematic code rather than fail. + +**Runtime issues** occur when compiled code behaves differently than expected. Most of the time, if you encounter an issue with React Compiler, it's a runtime issue. This typically happens when your code violates the Rules of React in subtle ways that the compiler couldn't detect, and the compiler mistakenly compiled a component it should have skipped. + +When debugging runtime issues, focus your efforts on finding Rules of React violations in the affected components that were not detected by the ESLint rule. The compiler relies on your code following these rules, and when they're broken in ways it can't detect, that's when runtime problems occur. + + +## Common Breaking Patterns {/*common-breaking-patterns*/} + +One of the main ways React Compiler can break your app is if your code was written to rely on memoization for correctness. This means your app depends on specific values being memoized to work properly. Since the compiler may memoize differently than your manual approach, this can lead to unexpected behavior like effects over-firing, infinite loops, or missing updates. + +Common scenarios where this occurs: + +- **Effects that rely on referential equality** - When effects depend on objects or arrays maintaining the same reference across renders +- **Dependency arrays that need stable references** - When unstable dependencies cause effects to fire too often or create infinite loops +- **Conditional logic based on reference checks** - When code uses referential equality checks for caching or optimization + +## Debugging Workflow {/*debugging-workflow*/} + +Follow these steps when you encounter issues: + +### Compiler Build Errors {/*compiler-build-errors*/} + +If you encounter a compiler error that unexpectedly breaks your build, this is likely a bug in the compiler. Report it to the [react/react](https://github.com/react/react/issues) repository with: +- The error message +- The code that caused the error +- Your React and compiler versions + +### Runtime Issues {/*runtime-issues*/} + +For runtime behavior issues: + +### 1. Temporarily Disable Compilation {/*temporarily-disable-compilation*/} + +Use `"use no memo"` to isolate whether an issue is compiler-related: + +```js +function ProblematicComponent() { + "use no memo"; // Skip compilation for this component + // ... rest of component +} +``` + +If the issue disappears, it's likely related to a Rules of React violation. + +You can also try removing manual memoization (useMemo, useCallback, memo) from the problematic component to verify that your app works correctly without any memoization. If the bug still occurs when all memoization is removed, you have a Rules of React violation that needs to be fixed. + +### 2. Fix Issues Step by Step {/*fix-issues-step-by-step*/} + +1. Identify the root cause (often memoization-for-correctness) +2. Test after each fix +3. Remove `"use no memo"` once fixed +4. Verify the component shows the ✨ badge in React DevTools + +## Reporting Compiler Bugs {/*reporting-compiler-bugs*/} + +If you believe you've found a compiler bug: + +1. **Verify it's not a Rules of React violation** - Check with ESLint +2. **Create a minimal reproduction** - Isolate the issue in a small example +3. **Test without the compiler** - Confirm the issue only occurs with compilation +4. **File an [issue](https://github.com/react/react/issues/new?template=compiler_bug_report.yml)**: + - React and compiler versions + - Minimal reproduction code + - Expected vs actual behavior + - Any error messages + +## Next Steps {/*next-steps*/} + +- Review the [Rules of React](/reference/rules) to prevent issues +- Check the [incremental adoption guide](/learn/react-compiler/incremental-adoption) for gradual rollout strategies \ No newline at end of file diff --git a/src/content/learn/react-compiler/installation.md b/src/content/learn/react-compiler/installation.md new file mode 100644 index 000000000..b386e866e --- /dev/null +++ b/src/content/learn/react-compiler/installation.md @@ -0,0 +1,263 @@ +--- +title: Installation +--- + +<Intro> +This guide will help you install and configure React Compiler in your React application. +</Intro> + +<YouWillLearn> + +* How to install React Compiler +* Basic configuration for different build tools +* How to verify your setup is working + +</YouWillLearn> + +## Prerequisites {/*prerequisites*/} + +React Compiler is designed to work best with React 19, but it also supports React 17 and 18. Learn more about [React version compatibility](/reference/react-compiler/target). + +## Installation {/*installation*/} + +Install React Compiler as a `devDependency`: + +<TerminalBlock> +npm install -D babel-plugin-react-compiler@latest +</TerminalBlock> + +Or with Yarn: + +<TerminalBlock> +yarn add -D babel-plugin-react-compiler@latest +</TerminalBlock> + +Or with pnpm: + +<TerminalBlock> +pnpm install -D babel-plugin-react-compiler@latest +</TerminalBlock> + +## Basic Setup {/*basic-setup*/} + +React Compiler is designed to work by default without any configuration. However, if you need to configure it in special circumstances (for example, to target React versions below 19), refer to the [compiler options reference](/reference/react-compiler/configuration). + +The setup process depends on your build tool. React Compiler includes a Babel plugin that integrates with your build pipeline. + +<Pitfall> +React Compiler must run **first** in your Babel plugin pipeline. The compiler needs the original source information for proper analysis, so it must process your code before other transformations. +</Pitfall> + +### Babel {/*babel*/} + +Create or update your `babel.config.js`: + +```js {3} +module.exports = { + plugins: [ + 'babel-plugin-react-compiler', // must run first! + // ... other plugins + ], + // ... other config +}; +``` + +### Vite {/*vite*/} + +If you use Vite with version 6.0.0 or later of `@vitejs/plugin-react`, you can use the `reactCompilerPreset`: + +<TerminalBlock> +npm install -D @rolldown/plugin-babel +</TerminalBlock> + +```js {3-4,9-11} +// vite.config.js +import { defineConfig } from 'vite'; +import react, { reactCompilerPreset } from '@vitejs/plugin-react'; +import babel from '@rolldown/plugin-babel'; + +export default defineConfig({ + plugins: [ + react(), + babel({ + presets: [reactCompilerPreset()] + }), + ], +}); +``` + +<Note> +In `@vitejs/plugin-react@6.0.0`, the inline Babel option was removed. If you're using an older version, you can use: + +```js +// vite.config.js +import { defineConfig } from 'vite'; +import react from '@vitejs/plugin-react'; + +export default defineConfig({ + plugins: [ + react({ + babel: { + plugins: ['babel-plugin-react-compiler'], + }, + }), + ], +}); +``` +</Note> + +Alternatively, you can use the Babel plugin directly with `@rolldown/plugin-babel`: + +```js {3,9} +// vite.config.js +import { defineConfig } from 'vite'; +import react from '@vitejs/plugin-react'; +import babel from '@rolldown/plugin-babel'; + +export default defineConfig({ + plugins: [ + react(), + babel({ + plugins: ['babel-plugin-react-compiler'], + }), + ], +}); +``` + +### Next.js {/*usage-with-nextjs*/} + +Please refer to the [Next.js docs](https://nextjs.org/docs/app/api-reference/next-config-js/reactCompiler) for more information. + +### React Router {/*usage-with-react-router*/} +Install `vite-plugin-babel`, and add the compiler's Babel plugin to it: + +<TerminalBlock> +npm install vite-plugin-babel +</TerminalBlock> + +```js {3-4,16} +// vite.config.js +import { defineConfig } from "vite"; +import babel from "vite-plugin-babel"; +import { reactRouter } from "@react-router/dev/vite"; + +const ReactCompilerConfig = { /* ... */ }; + +export default defineConfig({ + plugins: [ + reactRouter(), + babel({ + filter: /\.[jt]sx?$/, + babelConfig: { + presets: ["@babel/preset-typescript"], // if you use TypeScript + plugins: [ + ["babel-plugin-react-compiler", ReactCompilerConfig], + ], + }, + }), + ], +}); +``` + +### Webpack {/*usage-with-webpack*/} + +A community webpack loader is [now available here](https://github.com/SukkaW/react-compiler-webpack). + +### Expo {/*usage-with-expo*/} + +Please refer to [Expo's docs](https://docs.expo.dev/guides/react-compiler/) to enable and use the React Compiler in Expo apps. + +### Metro (React Native) {/*usage-with-react-native-metro*/} + +React Native uses Babel via Metro, so refer to the [Usage with Babel](#babel) section for installation instructions. + +### Rspack {/*usage-with-rspack*/} + +Please refer to [Rspack's docs](https://rspack.dev/guide/tech/react#react-compiler) to enable and use the React Compiler in Rspack apps. + +### Rsbuild {/*usage-with-rsbuild*/} + +Please refer to [Rsbuild's docs](https://rsbuild.dev/guide/framework/react#react-compiler) to enable and use the React Compiler in Rsbuild apps. + + +## ESLint Integration {/*eslint-integration*/} + +React Compiler includes an ESLint rule that helps identify code that can't be optimized. When the ESLint rule reports an error, it means the compiler will skip optimizing that specific component or hook. This is safe: the compiler will continue optimizing other parts of your codebase. You don't need to fix all violations immediately. Address them at your own pace to gradually increase the number of optimized components. + +Install the ESLint plugin: + +<TerminalBlock> +npm install -D eslint-plugin-react-hooks@latest +</TerminalBlock> + +If you haven't already configured eslint-plugin-react-hooks, follow the [installation instructions in the readme](https://github.com/react/react/blob/main/packages/eslint-plugin-react-hooks/README.md#installation). The compiler rules are available in the `recommended-latest` preset. + +The ESLint rule will: +- Identify violations of the [Rules of React](/reference/rules) +- Show which components can't be optimized +- Provide helpful error messages for fixing issues + +## Verify Your Setup {/*verify-your-setup*/} + +After installation, verify that React Compiler is working correctly. + +### Check React DevTools {/*check-react-devtools*/} + +Components optimized by React Compiler will show a "Memo ✨" badge in React DevTools: + +1. Install the [React Developer Tools](/learn/react-developer-tools) browser extension +2. Open your app in development mode +3. Open React DevTools +4. Look for the ✨ emoji next to component names + +If the compiler is working: +- Components will show a "Memo ✨" badge in React DevTools +- Expensive calculations will be automatically memoized +- No manual `useMemo` is required + +### Check Build Output {/*check-build-output*/} + +You can also verify the compiler is running by checking your build output. The compiled code will include automatic memoization logic that the compiler adds automatically. + +```js +import { c as _c } from "react/compiler-runtime"; +export default function MyApp() { + const $ = _c(1); + let t0; + if ($[0] === Symbol.for("react.memo_cache_sentinel")) { + t0 = <div>Hello World</div>; + $[0] = t0; + } else { + t0 = $[0]; + } + return t0; +} + +``` + +## Troubleshooting {/*troubleshooting*/} + +### Opting out specific components {/*opting-out-specific-components*/} + +If a component is causing issues after compilation, you can temporarily opt it out using the `"use no memo"` directive: + +```js +function ProblematicComponent() { + "use no memo"; + // Component code here +} +``` + +This tells the compiler to skip optimization for this specific component. You should fix the underlying issue and remove the directive once resolved. + +For more troubleshooting help, see the [debugging guide](/learn/react-compiler/debugging). + +## Next Steps {/*next-steps*/} + +Now that you have React Compiler installed, learn more about: + +- [React version compatibility](/reference/react-compiler/target) for React 17 and 18 +- [Configuration options](/reference/react-compiler/configuration) to customize the compiler +- [Incremental adoption strategies](/learn/react-compiler/incremental-adoption) for existing codebases +- [Debugging techniques](/learn/react-compiler/debugging) for troubleshooting issues +- [Compiling Libraries guide](/reference/react-compiler/compiling-libraries) for compiling your React library diff --git a/src/content/learn/tutorial-tic-tac-toe.md b/src/content/learn/tutorial-tic-tac-toe.md index 5c5c98cc8..536c026ec 100644 --- a/src/content/learn/tutorial-tic-tac-toe.md +++ b/src/content/learn/tutorial-tic-tac-toe.md @@ -922,19 +922,32 @@ body { ### React Developer Tools {/*react-developer-tools*/} +<<<<<<< HEAD React DevTools ຊ່ວຍໃຫ້ທ່ານກວດ prop ແລະ state ຂອງ Component React ຂອງທ່ານ. ທ່ານສາມາດຫາແທັບ React DevTools ໃນດ້ານລຸ່ມຂອງສ່ວນ _browser_ ໃນ CodeSandbox: +======= +React Developer Tools let you check the props and the state of your React components. It is available as a [Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi?hl=en), [Firefox](https://addons.mozilla.org/en-US/firefox/addon/react-devtools/), and [Edge](https://microsoftedge.microsoft.com/addons/detail/react-developer-tools/gpphkfbcpidddadnkolkpfckpihlkkil) browser extension. +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca -![React DevTools in CodeSandbox](../images/tutorial/codesandbox-devtools.png) +After you install it, a new *Components* tab will appear in your browser Developer Tools for sites using React. If you're following along in CodeSandbox, you'd need to first open your sandbox preview in a new tab: +<<<<<<< HEAD ເພື່ອກວດແຕ່ລະ component ເທິງໜ້າຈໍ, ໃຊ້ປຸ່ມທີ່ຢູ່ມຸມຊ້າຍດ້ານເທິງຂອງ React DevTools: +======= +![opening in new tab](../images/tutorial/sandbox-new-tab.png) +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca -![Selecting components on the page with React DevTools](../images/tutorial/devtools-select.gif) +Then, on the preview page, open your browser's DevTools and find the *Components* tab: -<Note> +![components tab](../images/tutorial/components-tab.png) +<<<<<<< HEAD ສຳລັບ local development, React DevTools ແມ່ນມີໃນ browser extension [Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi?hl=en), [Firefox](https://addons.mozilla.org/en-US/firefox/addon/react-devtools/), ແລະ [Edge](https://microsoftedge.microsoft.com/addons/detail/react-developer-tools/gpphkfbcpidddadnkolkpfckpihlkkil). ຕິດຕັ້ງມັນ, ແລະ ແທັບ *Components* ຈະສະແດງໃນ browser Developer Tools ສຳລັບໜ້າທີ່ໃຊ້ React. +======= +To inspect a particular component on the screen, use the button in the top left corner of the Components tab: + +![inspecting with devtools](../images/tutorial/devtools-inspect.gif) +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca -</Note> ## ເຮັດເກມໃຫ້ແລ້ວ {/*completing-the-game*/} diff --git a/src/content/reference/eslint-plugin-react-hooks/lints/incompatible-library.md b/src/content/reference/eslint-plugin-react-hooks/lints/incompatible-library.md new file mode 100644 index 000000000..6acffb227 --- /dev/null +++ b/src/content/reference/eslint-plugin-react-hooks/lints/incompatible-library.md @@ -0,0 +1,138 @@ +--- +title: incompatible-library +--- + +<Intro> + +Validates against usage of libraries which are incompatible with memoization (manual or automatic). + +</Intro> + +<Note> + +These libraries were designed before React's memoization rules were fully documented. They made the correct choices at the time to optimize for ergonomic ways to keep components just the right amount of reactive as app state changes. While these legacy patterns worked, we have since discovered that it's incompatible with React's programming model. We will continue working with library authors to migrate these libraries to use patterns that follow the Rules of React. + +</Note> + +## Rule Details {/*rule-details*/} + +Some libraries use patterns that aren't supported by React. When the linter detects usages of these APIs from a [known list](https://github.com/react/react/blob/main/compiler/packages/babel-plugin-react-compiler/src/HIR/DefaultModuleTypeProvider.ts), it flags them under this rule. This means that React Compiler can automatically skip over components that use these incompatible APIs, in order to avoid breaking your app. + +```js +// Example of how memoization breaks with these libraries +function Form() { + const { watch } = useForm(); + + // ❌ This value will never update, even when 'name' field changes + const name = useMemo(() => watch('name'), [watch]); + + return <div>Name: {name}</div>; // UI appears "frozen" +} +``` + +React Compiler automatically memoizes values following the Rules of React. If something breaks with manual `useMemo`, it will also break the compiler's automatic optimization. This rule helps identify these problematic patterns. + +<DeepDive> + +#### Designing APIs that follow the Rules of React {/*designing-apis-that-follow-the-rules-of-react*/} + +One question to think about when designing a library API or hook is whether calling the API can be safely memoized with `useMemo`. If it can't, then both manual and React Compiler memoizations will break your user's code. + +For example, one such incompatible pattern is "interior mutability". Interior mutability is when an object or function keeps its own hidden state that changes over time, even though the reference to it stays the same. Think of it like a box that looks the same on the outside but secretly rearranges its contents. React can't tell anything changed because it only checks if you gave it a different box, not what's inside. This breaks memoization, since React relies on the outer object (or function) changing if part of its value has changed. + +As a rule of thumb, when designing React APIs, think about whether `useMemo` would break it: + +```js +function Component() { + const { someFunction } = useLibrary(); + // it should always be safe to memoize functions like this + const result = useMemo(() => someFunction(), [someFunction]); +} +``` + +Instead, design APIs that return immutable state and use explicit update functions: + +```js +// ✅ Good: Return immutable state that changes reference when updated +function Component() { + const { field, updateField } = useLibrary(); + // this is always safe to memo + const greeting = useMemo(() => `Hello, ${field.name}!`, [field.name]); + + return ( + <div> + <input + value={field.name} + onChange={(e) => updateField('name', e.target.value)} + /> + <p>{greeting}</p> + </div> + ); +} +``` + +</DeepDive> + +### Invalid {/*invalid*/} + +Examples of incorrect code for this rule: + +```js +// ❌ react-hook-form `watch` +function Component() { + const {watch} = useForm(); + const value = watch('field'); // Interior mutability + return <div>{value}</div>; +} + +// ❌ TanStack Table `useReactTable` +function Component({data}) { + const table = useReactTable({ + data, + columns, + getCoreRowModel: getCoreRowModel(), + }); + // table instance uses interior mutability + return <Table table={table} />; +} +``` + +<Pitfall> + +#### MobX {/*mobx*/} + +MobX patterns like `observer` also break memoization assumptions, but the linter does not yet detect them. If you rely on MobX and find that your app doesn't work with React Compiler, you may need to use the `"use no memo" directive`. + +```js +// ❌ MobX `observer` +const Component = observer(() => { + const [timer] = useState(() => new Timer()); + return <span>Seconds passed: {timer.secondsPassed}</span>; +}); +``` + +</Pitfall> + +### Valid {/*valid*/} + +Examples of correct code for this rule: + +```js +// ✅ For react-hook-form, use `useWatch`: +function Component() { + const {register, control} = useForm(); + const watchedValue = useWatch({ + control, + name: 'field' + }); + + return ( + <> + <input {...register('field')} /> + <div>Current value: {watchedValue}</div> + </> + ); +} +``` + +Some other libraries do not yet have alternative APIs that are compatible with React's memoization model. If the linter doesn't automatically skip over your components or hooks that call these APIs, please [file an issue](https://github.com/react/react/issues) so we can add it to the linter. diff --git a/src/content/reference/react-dom/components/common.md b/src/content/reference/react-dom/components/common.md index 601370da5..def54ae5c 100644 --- a/src/content/reference/react-dom/components/common.md +++ b/src/content/reference/react-dom/components/common.md @@ -36,7 +36,7 @@ These special React props are supported for all built-in components: * `suppressHydrationWarning`: A boolean. If you use [server rendering,](/reference/react-dom/server) normally there is a warning when the server and the client render different content. In some rare cases (like timestamps), it is very hard or impossible to guarantee an exact match. If you set `suppressHydrationWarning` to `true`, React will not warn you about mismatches in the attributes and the content of that element. It only works one level deep, and is intended to be used as an escape hatch. Don't overuse it. [Read about suppressing hydration errors.](/reference/react-dom/client/hydrateRoot#suppressing-unavoidable-hydration-mismatch-errors) -* `style`: An object with CSS styles, for example `{ fontWeight: 'bold', margin: 20 }`. Similarly to the DOM [`style`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/style) property, the CSS property names need to be written as `camelCase`, for example `fontWeight` instead of `font-weight`. You can pass strings or numbers as values. If you pass a number, like `width: 100`, React will automatically append `px` ("pixels") to the value unless it's a [unitless property.](https://github.com/facebook/react/blob/81d4ee9ca5c405dce62f64e61506b8e155f38d8d/packages/react-dom-bindings/src/shared/CSSProperty.js#L8-L57) We recommend using `style` only for dynamic styles where you don't know the style values ahead of time. In other cases, applying plain CSS classes with `className` is more efficient. [Read more about `className` and `style`.](#applying-css-styles) +* `style`: An object with CSS styles, for example `{ fontWeight: 'bold', margin: 20 }`. Similarly to the DOM [`style`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/style) property, the CSS property names need to be written as `camelCase`, for example `fontWeight` instead of `font-weight`. You can pass strings or numbers as values. If you pass a number, like `width: 100`, React will automatically append `px` ("pixels") to the value unless it's a [unitless property.](https://github.com/react/react/blob/81d4ee9ca5c405dce62f64e61506b8e155f38d8d/packages/react-dom-bindings/src/shared/CSSProperty.js#L8-L57) We recommend using `style` only for dynamic styles where you don't know the style values ahead of time. In other cases, applying plain CSS classes with `className` is more efficient. [Read more about `className` and `style`.](#applying-css-styles) These standard DOM props are also supported for all built-in components: diff --git a/src/content/reference/react-dom/components/form.md b/src/content/reference/react-dom/components/form.md index 4b7d5d8a0..6fa47d53a 100644 --- a/src/content/reference/react-dom/components/form.md +++ b/src/content/reference/react-dom/components/form.md @@ -56,9 +56,51 @@ To create interactive controls for submitting information, render the [built-in ## Usage {/*usage*/} -### Handle form submission on the client {/*handle-form-submission-on-the-client*/} +### Handle form submission with an event handler {/*handle-form-submission-with-an-event-handler*/} +<<<<<<< HEAD Pass a function to the `action` prop of form to run the function when the form is submitted. [`formData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) will be passed to the function as an argument so you can access the data submitted by the form. This differs from the conventional [HTML action](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form#action), which only accepts URLs. +======= +Pass a function to the `onSubmit` event handler to run code when the form is submitted. By default, the browser sends the form data to the current URL and refreshes the page, so call [`e.preventDefault()`](https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault) to override that behavior. + +This example reads the submitted values with [`new FormData(e.target)`](https://developer.mozilla.org/en-US/docs/Web/API/FormData), which collects every field by its `name`. This keeps the inputs [uncontrolled](/reference/react-dom/components/input#reading-the-input-values-when-submitting-a-form). If you instead [control an input with state](/reference/react-dom/components/input#controlling-an-input-with-a-state-variable), read from that state on submit rather than from `FormData`. + +<Sandpack> + +```js src/App.js +export default function Search() { + function handleSubmit(e) { + // Prevent the browser from reloading the page + e.preventDefault(); + + // Read the form data + const form = e.target; + const formData = new FormData(form); + const query = formData.get("query"); + alert(`You searched for '${query}'`); + } + + return ( + <form onSubmit={handleSubmit}> + <input name="query" /> + <button type="submit">Search</button> + </form> + ); +} +``` + +</Sandpack> + +<Note> + +Reading form data with `onSubmit` works in every version of React and gives you direct access to the [submit event](https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit_event), so you can call `e.preventDefault()` and read the data yourself. Passing the function to the `action` prop instead runs the submission in a [Transition](/reference/react/useTransition). React then tracks the pending state, sends thrown errors to the nearest error boundary, and lets the form work with [`useActionState`](/reference/react/useActionState) and [`useOptimistic`](/reference/react/useOptimistic). An `action` can also be a [Server Function](/reference/rsc/server-functions), which `onSubmit` does not support. + +</Note> + +### Handle form submission with an action prop {/*handle-form-submission-with-an-action-prop*/} + +Pass a function to the `action` prop of form to run the function when the form is submitted. [`formData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) will be passed to the function as an argument so you can access the data submitted by the form. This differs from the conventional [HTML action](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form#action), which only accepts URLs. Unlike `onSubmit`, an `action` runs in a [Transition](/reference/react/useTransition) and calling `e.preventDefault()` isn't needed. After the `action` function succeeds, all uncontrolled field elements in the form are reset. +>>>>>>> 6be2b020a0cabf2fd6dbff5c42c399b8ac323bca <Sandpack> diff --git a/src/content/reference/react-dom/server/renderToPipeableStream.md b/src/content/reference/react-dom/server/renderToPipeableStream.md index b027d1b3b..bce7c6f2d 100644 --- a/src/content/reference/react-dom/server/renderToPipeableStream.md +++ b/src/content/reference/react-dom/server/renderToPipeableStream.md @@ -59,7 +59,7 @@ On the client, call [`hydrateRoot`](/reference/react-dom/client/hydrateRoot) to * **optional** `onError`: A callback that fires whenever there is a server error, whether [recoverable](#recovering-from-errors-outside-the-shell) or [not.](#recovering-from-errors-inside-the-shell) By default, this only calls `console.error`. If you override it to [log crash reports,](#logging-crashes-on-the-server) make sure that you still call `console.error`. You can also use it to [adjust the status code](#setting-the-status-code) before the shell is emitted. * **optional** `onShellReady`: A callback that fires right after the [initial shell](#specifying-what-goes-into-the-shell) has been rendered. You can [set the status code](#setting-the-status-code) and call `pipe` here to start streaming. React will [stream the additional content](#streaming-more-content-as-it-loads) after the shell along with the inline `<script>` tags that place that replace the HTML loading fallbacks with the content. * **optional** `onShellError`: A callback that fires if there was an error rendering the initial shell. It receives the error as an argument. No bytes were emitted from the stream yet, and neither `onShellReady` nor `onAllReady` will get called, so you can [output a fallback HTML shell.](#recovering-from-errors-inside-the-shell) - * **optional** `progressiveChunkSize`: The number of bytes in a chunk. [Read more about the default heuristic.](https://github.com/facebook/react/blob/14c2be8dac2d5482fda8a0906a31d239df8551fc/packages/react-server/src/ReactFizzServer.js#L210-L225) + * **optional** `progressiveChunkSize`: The number of bytes in a chunk. [Read more about the default heuristic.](https://github.com/react/react/blob/14c2be8dac2d5482fda8a0906a31d239df8551fc/packages/react-server/src/ReactFizzServer.js#L210-L225) #### Returns {/*returns*/} @@ -284,17 +284,7 @@ Streaming does not need to wait for React itself to load in the browser, or for <Note> -**Only Suspense-enabled data sources will activate the Suspense component.** They include: - -- Data fetching with Suspense-enabled frameworks like [Relay](https://relay.dev/docs/guided-tour/rendering/loading-states/) and [Next.js](https://nextjs.org/docs/getting-started/react-essentials) -- Lazy-loading component code with [`lazy`](/reference/react/lazy) -- Reading the value of a Promise with [`use`](/reference/react/use) - -Suspense **does not** detect when data is fetched inside an Effect or event handler. - -The exact way you would load data in the `Posts` component above depends on your framework. If you use a Suspense-enabled framework, you'll find the details in its data fetching documentation. - -Suspense-enabled data fetching without the use of an opinionated framework is not yet supported. The requirements for implementing a Suspense-enabled data source are unstable and undocumented. An official API for integrating data sources with Suspense will be released in a future version of React. +Only data read from a source that [activates a Suspense boundary](/reference/react/Suspense#what-activates-a-suspense-boundary), such as a Promise read with [`use`](/reference/react/use), will suspend during rendering. Suspense does not detect data fetched inside an Effect or event handler. </Note> diff --git a/src/content/reference/react-dom/server/renderToReadableStream.md b/src/content/reference/react-dom/server/renderToReadableStream.md index f3e862124..7ee0a0bce 100644 --- a/src/content/reference/react-dom/server/renderToReadableStream.md +++ b/src/content/reference/react-dom/server/renderToReadableStream.md @@ -57,7 +57,7 @@ On the client, call [`hydrateRoot`](/reference/react-dom/client/hydrateRoot) to * **optional** `namespaceURI`: A string with the root [namespace URI](https://developer.mozilla.org/en-US/docs/Web/API/Document/createElementNS#important_namespace_uris) for the stream. Defaults to regular HTML. Pass `'http://www.w3.org/2000/svg'` for SVG or `'http://www.w3.org/1998/Math/MathML'` for MathML. * **optional** `nonce`: A [`nonce`](http://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#nonce) string to allow scripts for [`script-src` Content-Security-Policy](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src). * **optional** `onError`: A callback that fires whenever there is a server error, whether [recoverable](#recovering-from-errors-outside-the-shell) or [not.](#recovering-from-errors-inside-the-shell) By default, this only calls `console.error`. If you override it to [log crash reports,](#logging-crashes-on-the-server) make sure that you still call `console.error`. You can also use it to [adjust the status code](#setting-the-status-code) before the shell is emitted. - * **optional** `progressiveChunkSize`: The number of bytes in a chunk. [Read more about the default heuristic.](https://github.com/facebook/react/blob/14c2be8dac2d5482fda8a0906a31d239df8551fc/packages/react-server/src/ReactFizzServer.js#L210-L225) + * **optional** `progressiveChunkSize`: The number of bytes in a chunk. [Read more about the default heuristic.](https://github.com/react/react/blob/14c2be8dac2d5482fda8a0906a31d239df8551fc/packages/react-server/src/ReactFizzServer.js#L210-L225) * **optional** `signal`: An [abort signal](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal) that lets you [abort server rendering](#aborting-server-rendering) and render the rest on the client. @@ -283,17 +283,7 @@ Streaming does not need to wait for React itself to load in the browser, or for <Note> -**Only Suspense-enabled data sources will activate the Suspense component.** They include: - -- Data fetching with Suspense-enabled frameworks like [Relay](https://relay.dev/docs/guided-tour/rendering/loading-states/) and [Next.js](https://nextjs.org/docs/getting-started/react-essentials) -- Lazy-loading component code with [`lazy`](/reference/react/lazy) -- Reading the value of a Promise with [`use`](/reference/react/use) - -Suspense **does not** detect when data is fetched inside an Effect or event handler. - -The exact way you would load data in the `Posts` component above depends on your framework. If you use a Suspense-enabled framework, you'll find the details in its data fetching documentation. - -Suspense-enabled data fetching without the use of an opinionated framework is not yet supported. The requirements for implementing a Suspense-enabled data source are unstable and undocumented. An official API for integrating data sources with Suspense will be released in a future version of React. +Only data read from a source that [activates a Suspense boundary](/reference/react/Suspense#what-activates-a-suspense-boundary), such as a Promise read with [`use`](/reference/react/use), will suspend during rendering. Suspense does not detect data fetched inside an Effect or event handler. </Note> diff --git a/src/content/reference/react-dom/static/prerender.md b/src/content/reference/react-dom/static/prerender.md new file mode 100644 index 000000000..811e5fc60 --- /dev/null +++ b/src/content/reference/react-dom/static/prerender.md @@ -0,0 +1,314 @@ +--- +title: prerender +--- + +<Intro> + +`prerender` renders a React tree to a static HTML string using a [Web Stream](https://developer.mozilla.org/en-US/docs/Web/API/Streams_API). + +```js +const {prelude, postponed} = await prerender(reactNode, options?) +``` + +</Intro> + +<InlineToc /> + +<Note> + +This API depends on [Web Streams.](https://developer.mozilla.org/en-US/docs/Web/API/Streams_API) For Node.js, use [`prerenderToNodeStream`](/reference/react-dom/static/prerenderToNodeStream) instead. + +</Note> + +--- + +## Reference {/*reference*/} + +### `prerender(reactNode, options?)` {/*prerender*/} + +Call `prerender` to render your app to static HTML. + +```js +import { prerender } from 'react-dom/static'; + +async function handler(request, response) { + const {prelude} = await prerender(<App />, { + bootstrapScripts: ['/main.js'] + }); + return new Response(prelude, { + headers: { 'content-type': 'text/html' }, + }); +} +``` + +On the client, call [`hydrateRoot`](/reference/react-dom/client/hydrateRoot) to make the server-generated HTML interactive. + +[See more examples below.](#usage) + +#### Parameters {/*parameters*/} + +* `reactNode`: A React node you want to render to HTML. For example, a JSX node like `<App />`. It is expected to represent the entire document, so the App component should render the `<html>` tag. + +* **optional** `options`: An object with static generation options. + * **optional** `bootstrapScriptContent`: If specified, this string will be placed in an inline `<script>` tag. + * **optional** `bootstrapScripts`: An array of string URLs for the `<script>` tags to emit on the page. Use this to include the `<script>` that calls [`hydrateRoot`.](/reference/react-dom/client/hydrateRoot) Omit it if you don't want to run React on the client at all. + * **optional** `bootstrapModules`: Like `bootstrapScripts`, but emits [`<script type="module">`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules) instead. + * **optional** `identifierPrefix`: A string prefix React uses for IDs generated by [`useId`.](/reference/react/useId) Useful to avoid conflicts when using multiple roots on the same page. Must be the same prefix as passed to [`hydrateRoot`.](/reference/react-dom/client/hydrateRoot#parameters) + * **optional** `namespaceURI`: A string with the root [namespace URI](https://developer.mozilla.org/en-US/docs/Web/API/Document/createElementNS#important_namespace_uris) for the stream. Defaults to regular HTML. Pass `'http://www.w3.org/2000/svg'` for SVG or `'http://www.w3.org/1998/Math/MathML'` for MathML. + * **optional** `onError`: A callback that fires whenever there is a server error, whether [recoverable](/reference/react-dom/server/renderToReadableStream#recovering-from-errors-outside-the-shell) or [not.](/reference/react-dom/server/renderToReadableStream#recovering-from-errors-inside-the-shell) By default, this only calls `console.error`. If you override it to [log crash reports,](/reference/react-dom/server/renderToReadableStream#logging-crashes-on-the-server) make sure that you still call `console.error`. You can also use it to [adjust the status code](/reference/react-dom/server/renderToReadableStream#setting-the-status-code) before the shell is emitted. + * **optional** `progressiveChunkSize`: The number of bytes in a chunk. [Read more about the default heuristic.](https://github.com/react/react/blob/14c2be8dac2d5482fda8a0906a31d239df8551fc/packages/react-server/src/ReactFizzServer.js#L210-L225) + * **optional** `signal`: An [abort signal](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal) that lets you [abort prerendering](#aborting-prerendering) and render the rest on the client. + +#### Returns {/*returns*/} + +`prerender` returns a Promise: +- If rendering the is successful, the Promise will resolve to an object containing: + - `prelude`: a [Web Stream](https://developer.mozilla.org/en-US/docs/Web/API/Streams_API) of HTML. You can use this stream to send a response in chunks, or you can read the entire stream into a string. + - `postponed`: a JSON-serializeable, opaque object that can be passed to [`resume`](/reference/react-dom/server/resume) if `prerender` did not finish. Otherwise `null` indicating that the `prelude` contains all the content and no resume is necessary. +- If rendering fails, the Promise will be rejected. [Use this to output a fallback shell.](/reference/react-dom/server/renderToReadableStream#recovering-from-errors-inside-the-shell) + +#### Caveats {/*caveats*/} + +`nonce` is not an available option when prerendering. Nonces must be unique per request and if you use nonces to secure your application with [CSP](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CSP) it would be inappropriate and insecure to include the nonce value in the prerender itself. + +<Note> + +### When should I use `prerender`? {/*when-to-use-prerender*/} + +The static `prerender` API is used for static server-side generation (SSG). Unlike `renderToString`, `prerender` waits for all data to load before resolving. This makes it suitable for generating static HTML for a full page, including data that needs to be fetched using Suspense. To stream content as it loads, use a streaming server-side render (SSR) API like [renderToReadableStream](/reference/react-dom/server/renderToReadableStream). + +`prerender` can be aborted and later either continued with `resumeAndPrerender` or resumed with `resume` to support partial pre-rendering. + +</Note> + +--- + +## Usage {/*usage*/} + +### Rendering a React tree to a stream of static HTML {/*rendering-a-react-tree-to-a-stream-of-static-html*/} + +Call `prerender` to render your React tree to static HTML into a [Readable Web Stream:](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream): + +```js [[1, 4, "<App />"], [2, 5, "['/main.js']"]] +import { prerender } from 'react-dom/static'; + +async function handler(request) { + const {prelude} = await prerender(<App />, { + bootstrapScripts: ['/main.js'] + }); + return new Response(prelude, { + headers: { 'content-type': 'text/html' }, + }); +} +``` + +Along with the <CodeStep step={1}>root component</CodeStep>, you need to provide a list of <CodeStep step={2}>bootstrap `<script>` paths</CodeStep>. Your root component should return **the entire document including the root `<html>` tag.** + +For example, it might look like this: + +```js [[1, 1, "App"]] +export default function App() { + return ( + <html> + <head> + <meta charSet="utf-8" /> + <meta name="viewport" content="width=device-width, initial-scale=1" /> + <link rel="stylesheet" href="/styles.css"></link> + <title>My app + + + + + + ); +} +``` + +React will inject the [doctype](https://developer.mozilla.org/en-US/docs/Glossary/Doctype) and your bootstrap ` +``` + +On the client, your bootstrap script should [hydrate the entire `document` with a call to `hydrateRoot`:](/reference/react-dom/client/hydrateRoot#hydrating-an-entire-document) + +```js [[1, 4, ""]] +import { hydrateRoot } from 'react-dom/client'; +import App from './App.js'; + +hydrateRoot(document, ); +``` + +This will attach event listeners to the static server-generated HTML and make it interactive. + + + +#### Reading CSS and JS asset paths from the build output {/*reading-css-and-js-asset-paths-from-the-build-output*/} + +The final asset URLs (like JavaScript and CSS files) are often hashed after the build. For example, instead of `styles.css` you might end up with `styles.123456.css`. Hashing static asset filenames guarantees that every distinct build of the same asset will have a different filename. This is useful because it lets you safely enable long-term caching for static assets: a file with a certain name would never change content. + +However, if you don't know the asset URLs until after the build, there's no way for you to put them in the source code. For example, hardcoding `"/styles.css"` into JSX like earlier wouldn't work. To keep them out of your source code, your root component can read the real filenames from a map passed as a prop: + +```js {1,6} +export default function App({ assetMap }) { + return ( + + + My app + + + ... + + ); +} +``` + +On the server, render `` and pass your `assetMap` with the asset URLs: + +```js {1-5,8,9} +// You'd need to get this JSON from your build tooling, e.g. read it from the build output. +const assetMap = { + 'styles.css': '/styles.123456.css', + 'main.js': '/main.123456.js' +}; + +async function handler(request) { + const {prelude} = await prerender(, { + bootstrapScripts: [assetMap['/main.js']] + }); + return new Response(prelude, { + headers: { 'content-type': 'text/html' }, + }); +} +``` + +Since your server is now rendering ``, you need to render it with `assetMap` on the client too to avoid hydration errors. You can serialize and pass `assetMap` to the client like this: + +```js {9-10} +// You'd need to get this JSON from your build tooling. +const assetMap = { + 'styles.css': '/styles.123456.css', + 'main.js': '/main.123456.js' +}; + +async function handler(request) { + const {prelude} = await prerender(, { + // Careful: It's safe to stringify() this because this data isn't user-generated. + bootstrapScriptContent: `window.assetMap = ${JSON.stringify(assetMap)};`, + bootstrapScripts: [assetMap['/main.js']], + }); + return new Response(prelude, { + headers: { 'content-type': 'text/html' }, + }); +} +``` + +In the example above, the `bootstrapScriptContent` option adds an extra inline ` +``` + +On the client, your bootstrap script should [hydrate the entire `document` with a call to `hydrateRoot`:](/reference/react-dom/client/hydrateRoot#hydrating-an-entire-document) + +```js [[1, 4, ""]] +import { hydrateRoot } from 'react-dom/client'; +import App from './App.js'; + +hydrateRoot(document, ); +``` + +This will attach event listeners to the static server-generated HTML and make it interactive. + + + +#### Reading CSS and JS asset paths from the build output {/*reading-css-and-js-asset-paths-from-the-build-output*/} + +The final asset URLs (like JavaScript and CSS files) are often hashed after the build. For example, instead of `styles.css` you might end up with `styles.123456.css`. Hashing static asset filenames guarantees that every distinct build of the same asset will have a different filename. This is useful because it lets you safely enable long-term caching for static assets: a file with a certain name would never change content. + +However, if you don't know the asset URLs until after the build, there's no way for you to put them in the source code. For example, hardcoding `"/styles.css"` into JSX like earlier wouldn't work. To keep them out of your source code, your root component can read the real filenames from a map passed as a prop: + +```js {1,6} +export default function App({ assetMap }) { + return ( + + + My app + + + ... + + ); +} +``` + +On the server, render `` and pass your `assetMap` with the asset URLs: + +```js {1-5,8,9} +// You'd need to get this JSON from your build tooling, e.g. read it from the build output. +const assetMap = { + 'styles.css': '/styles.123456.css', + 'main.js': '/main.123456.js' +}; + +app.use('/', async (request, response) => { + const { prelude } = await prerenderToNodeStream(, { + bootstrapScripts: [assetMap['/main.js']] + }); + + response.setHeader('Content-Type', 'text/html'); + prelude.pipe(response); +}); +``` + +Since your server is now rendering ``, you need to render it with `assetMap` on the client too to avoid hydration errors. You can serialize and pass `assetMap` to the client like this: + +```js {9-10} +// You'd need to get this JSON from your build tooling. +const assetMap = { + 'styles.css': '/styles.123456.css', + 'main.js': '/main.123456.js' +}; + +app.use('/', async (request, response) => { + const { prelude } = await prerenderToNodeStream(, { + // Careful: It's safe to stringify() this because this data isn't user-generated. + bootstrapScriptContent: `window.assetMap = ${JSON.stringify(assetMap)};`, + bootstrapScripts: [assetMap['/main.js']], + }); + + response.setHeader('Content-Type', 'text/html'); + prelude.pipe(response); +}); +``` + +In the example above, the `bootstrapScriptContent` option adds an extra inline `