Metro babel transformer doesn't recognize .cjs config files (babel.config.cjs, .babelrc.cjs)

Description

The @react-native/metro-babel-transformer doesn't recognize .cjs babel config files, which causes silent failures when projects use "type": "module" in their package.json.

Problem

In @react-native/metro-babel-transformer/src/index.js (lines 74-88), the transformer only searches for:

.babelrc
.babelrc.js
babel.config.js

When a project has "type": "module" in package.json:

.js files are treated as ES modules by Node.js
Babel config files that use module.exports = function(api) {...} (CommonJS) must use the .cjs extension
Metro silently falls back to the default preset, ignoring custom plugins

This causes hard-to-debug issues. In my case, the react-native-worklets/plugin wasn't being applied, resulting in runtime errors like "Failed to create a worklet" with no indication that the babel config wasn't being loaded.

Expected behavior

Metro should also search for:

.babelrc.cjs
babel.config.cjs

This aligns with Babel's own configuration file resolution which supports .cjs extensions.

Workaround

Use extendsBabelConfigPath in Metro config:

// metro.config.cjs

const customConfig = {
  transformer: {
    extendsBabelConfigPath: path.resolve(__dirname, 'babel.config.cjs'),
  },
};

Environment

React Native: 0.81.5
Node.js: 24.x
pnpm monorepo with "type": "module" in package.json

Warning

Missing reproducer: We could not detect a reproducible example in your issue report. Reproducers are mandatory and we can accept only one of those as a valid reproducer:

For majority of bugs: send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.
If your bug is UI related: a Snack
If your bug is build/upgrade related: a project using our Reproducer Template

You can read more about about it on our website: How to report a bug.

Transferred to react/react-native, since the Babel config loading logic lives here, not in Metro itself.

Thanks for the report - seems like a legitimate expectation that discovery should mirror Babel's - or at least support .cjs.

Warning

Could not parse version: We could not find or parse the version number of React Native in your issue report. Please use the template, and report your version including major, minor, and patch numbers - e.g. 0.76.2.

Warning

Could not parse version: We could not find or parse the version number of React Native in your issue report. Please use the template, and report your version including major, minor, and patch numbers - e.g. 0.76.2.

This issue is waiting for author's feedback since 24 days. Please provide the requested feedback or this will be closed in 7 days.

Navigation Menu

Repository navigation

Metro babel transformer doesn't recognize .cjs config files (babel.config.cjs, .babelrc.cjs) #58525

Description

Problem

Expected behavior

Workaround

Environment

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Metro babel transformer doesn't recognize .cjs config files (babel.config.cjs, .babelrc.cjs) #58525

Description

Description

Problem

Expected behavior

Workaround

Environment

Activity

react-native-bot commented on Sep 14, 2026

robhogan commented on Sep 14, 2026

react-native-bot commented on Sep 14, 2026

react-native-bot commented on Sep 14, 2026

react-native-bot commented on Oct 9, 2026

react-native-bot commented on Oct 9, 2026

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions