🔎 Search Terms
export void export reserved export null
🕗 Version & Regression Information
- Reproducible since typescript v4. In older releases, it doesn't export anything. I also tried the latest dev release (5.9.0-dev.20250716)
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about
exports
⏯ Playground Link
Playground (important: lang:javascript)
💻 Code
Using the following tsconfig.json:
{
"compilerOptions": {
"target": "esnext",
"lib": ["esnext"],
"module": "esnext",
"allowJs": true,
"checkJs": true,
"declaration": true,
"declarationMap": true,
"outDir": "./dist",
"emitDeclarationOnly": true,
"strict": true,
"noImplicitAny": true,
"moduleResolution": "bundler"
}
}
I compile declaration files for this code ${project}/schema.js (only happens when compiling javascript):
const _null = {}
const $void = {}
export { _null as null, $void as void }
🙁 Actual behavior
The produced declaration file schema.d.ts is erroneous. It has duplicate identifiers:
declare const _null: {};
declare const $void: {};
export { _null as null, _null as null, $void as void, _void as void };
🙂 Expected behavior
No duplicate identifiers:
declare const _null: {};
declare const $void: {};
export { _null as null, $void as void };
Additional information about the issue
For any reserved keyword, tsc always exports _{reserved} as {reserved}, whenever {reserved} is exported. Even though the variable _{reserved} does not exist.
It is only reproducible when compiling javascript.
🔎 Search Terms
export voidexport reservedexport null🕗 Version & Regression Information
exports⏯ Playground Link
Playground (important: lang:javascript)
💻 Code
Using the following
tsconfig.json:{ "compilerOptions": { "target": "esnext", "lib": ["esnext"], "module": "esnext", "allowJs": true, "checkJs": true, "declaration": true, "declarationMap": true, "outDir": "./dist", "emitDeclarationOnly": true, "strict": true, "noImplicitAny": true, "moduleResolution": "bundler" } }I compile declaration files for this code
${project}/schema.js(only happens when compiling javascript):🙁 Actual behavior
The produced declaration file
schema.d.tsis erroneous. It has duplicate identifiers:🙂 Expected behavior
No duplicate identifiers:
Additional information about the issue
For any reserved keyword,
tscalways exports_{reserved} as {reserved}, whenever{reserved}is exported. Even though the variable_{reserved}does not exist.It is only reproducible when compiling javascript.