4.x: DataTable fails: Error: Invalid data type. Data accepts either: DataTable || generator || Array || function

Found in my production project after the migration from 3.x to 4.x. It works well in 3.x
Maybe the bug has the same reason as #5632 and #5635.

You can reproduce it with the Quickstart project

mirao@rog:~/workspace/my$ codeceptjs run --verbose
***************************************
nodeInfo:  24.16.0
osInfo:  Linux 6.17 Ubuntu 24.04.4 LTS 24.04.4 LTS (Noble Numbat)
cpuInfo:  (16) x64 AMD Ryzen 7 9700X 8-Core Processor
chromeInfo:  149.0.7827.114
edgeInfo:  "N/A"
firefoxInfo:  151.0.3
safariInfo:  N/A
playwrightBrowsers:  "chromium: 149.0.7827.55, firefox: 151.0, webkit: 26.5"
If you need more detailed info, just run this: npx codeceptjs info
***************************************
Error: Invalid data type. Data accepts either: DataTable || generator || Array || function
    at DataTable (/home/mirao/workspace/my/node_modules/codeceptjs/lib/data/context.js:117:10)
    at DataTable (/home/mirao/workspace/my/node_modules/codeceptjs/lib/data/context.js:117:10)
    at DataTable (/home/mirao/workspace/my/tests/My_test.ts:9:1)
    at Object.<anonymous> (/home/mirao/workspace/my/tests/My_test.ts:11:2)
    at Module._compile (node:internal/modules/cjs/loader:1854:14)
    at Object.transformer (/home/mirao/workspace/my/node_modules/tsx/dist/register-BOkp8V6j.cjs:9:3176)
    at Module.load (node:internal/modules/cjs/loader:1577:32)
    at Module._load (node:internal/modules/cjs/loader:1379:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:255:19)
    at Module.require (node:internal/modules/cjs/loader:1600:12)

Invalid data type. Data accepts either: DataTable || generator || Array || function

Error: 
    at DataTable (/home/mirao/workspace/my/node_modules/codeceptjs/lib/data/context.js:117:10)
    at DataTable (/home/mirao/workspace/my/node_modules/codeceptjs/lib/data/context.js:117:10)
    at DataTable (/home/mirao/workspace/my/tests/My_test.ts:9:1)
    at Object.<anonymous> (/home/mirao/workspace/my/tests/My_test.ts:11:2)
    at Module._compile (node:internal/modules/cjs/loader:1854:14)
    at Object.transformer (/home/mirao/workspace/my/node_modules/tsx/dist/register-BOkp8V6j.cjs:9:3176)
    at Module.load (node:internal/modules/cjs/loader:1577:32)
    at Module._load (node:internal/modules/cjs/loader:1379:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:255:19)
    at Module.require (node:internal/modules/cjs/loader:1600:12)

tests/My_test.ts:

import { dataTable as DataTable } from 'codeceptjs';

Feature('My');

const cases = new DataTable(['input', 'expected']);
cases.add(['input1', 'expected1']);
cases.add(['input2', 'expected2']);

Data(cases).Scenario('test something',  ({ I, current }) => {
    I.say(`Input: ${current.input}, Expected: ${current.expected}`);
});

codecept.conf.ts:

import { setHeadlessWhen, setCommonPlugins } from '@codeceptjs/configure';
// turn on headless mode when running with HEADLESS=true environment variable
// export HEADLESS=true && npx codeceptjs run
setHeadlessWhen(process.env.HEADLESS);

// enable all common plugins https://github.com/codeceptjs/configure#setcommonplugins
setCommonPlugins();

export const config: CodeceptJS.MainConfig = {
  tests: './tests/*_test.ts',
  output: './output',
  helpers: {
    Playwright: {
      browser: 'chromium',
      url: 'http://localhost',
      show: true
    }
  },
  include: {
    I: './steps_file.ts'
  },
  noGlobals: true,
  plugins: {},
  name: 'my',
  require: ['tsx/cjs']
}

tsconfig.json:

{
  "compilerOptions": {
    "target": "ES2022",
    "lib": ["ES2022", "DOM"],
    "esModuleInterop": true,
    "module": "ESNext",
    "moduleResolution": "bundler",
    "strictNullChecks": false,
    "types": ["codeceptjs", "node"],
    "declaration": true,
    "skipLibCheck": true
  },
  "exclude": ["node_modules"]
}

Used SW:

CodeceptJS 4.0.7

AI suggests this fix:

diff --git a/lib/data/context.js b/lib/data/context.js
index c2e0bc2..b0744d2 100644
--- a/lib/data/context.js
+++ b/lib/data/context.js
@@ -83,7 +83,7 @@ function isTableDataRow(row) {
 }
 
 function detectDataType(dataTable) {
-  if (dataTable instanceof DataTable) {
+  if (dataTable instanceof DataTable || (dataTable && Array.isArray(dataTable.rows) && typeof dataTable.add === 'function')) {
     return dataTable.rows
   }

The bug was fixed by #5640 (4.1.0 beta 1), but there is one more issue SyntaxError: Unexpected token (1:3) then. I hit the issue also in 4.0 when I solved #5641 by a patch.

test:

const userRoles = new DataTable(["role", "sideBarMenu"]);
userRoles.add([Role.BLOCK_ADMIN, "blockAdmin"]);
userRoles.add([Role.SUPER_MENTOR, "superMentor"]);
userRoles.add([Role.MENTOR, "mentor"]);
userRoles.add([Role.USER, "teacher"]);
userRoles.add([Role.SCHOOL_ADMIN, "schoolAdmin"]);

Data(userRoles).Scenario("Set roles to the user", ({ current }) => {
    let entity_type: EntityType;
    let entity_id: string;

    switch (current.role) {
        default:
        case Role.USER:
            entity_type = EntityType.TENANT;
            entity_id = String(tenantId);
            break;

        case Role.BLOCK_ADMIN:
            entity_type = EntityType.BLOCK;
            entity_id = String(blockId);
            break;

        case Role.SUPER_MENTOR:
        case Role.MENTOR:
            entity_type = EntityType.COURSE;
            entity_id = String(course.id);
            break;

        case Role.SCHOOL_ADMIN:
            entity_type = EntityType.SCHOOL;
            entity_id = String(school.id);
            break;
    }
    I.setUserRole(
        {
            role: current.role,
            entity_type,
            entity_id,
            user_id: userId,
        },
        adminToken,
    );
});

output:

  Course Mentoring disabled: Verify Dashboard tabs | {"role":"ROLE_BLOCK_ADMIN","sideBarMenu":"blockAdmin"}
 › Test Timeout: 600s
 › [Dir] /home/mirao/workspace/codeceptjs/tests/s4w
  Scenario()
Error in ({current})=>{if([Role.USER,Role.SCHOOL_ADMIN].includes(current.role)){I.click(sideBarMenu.dashboard[current.sideBarMenu].loc);for(const[index,text]of dashboardTabsPage[current.role].entries()){if(current.role===Role.SCHOOL_ADMIN&&(index===2||index===3)){I.dontSeeElement(dashboardTabsPage.tab.at(index+1))}else{I.seeTextEquals(text,dashboardTabsPage.tab.at(index+1))}}}else{I.dontSeeElement(sideBarMenu.dashboard[current.sideBarMenu].loc)}}
SyntaxError: Unexpected token (1:3)
    [6] Error | TypeError: Cannot read properties of undefined (reading 'role') undefined...
    [6] <teardown>  Stopping recording promises
 › <screenshot> Saving screenshot Course_Mentoring_disabled__Verify_Dashboard_tabs.failed.png
 › [Screenshot] output/Course_Mentoring_disabled__Verify_Dashboard_tabs.failed.png
  ✖ FAILED in 26ms

fix(data): detect DataTable structurally so Data() works under tsx/cjs (

The bug was fixed by #5640 (4.1.0 beta 1), but there is one more issue SyntaxError: Unexpected token (1:3) then.

Reported as #5679

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4.x: DataTable fails: Error: Invalid data type. Data accepts either: DataTable || generator || Array || function #5641

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4.x: DataTable fails: Error: Invalid data type. Data accepts either: DataTable || generator || Array || function #5641

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mirao commented on Jun 16, 2026

mirao commented on Jun 18, 2026

mirao commented on Aug 6, 2026

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