[Bug]: transformIgnorePatterns is not considered for files transformations

[malopgrics]

Version

30.0.5, also reproduced with 29.7.0

EDIT :

With the suggestions provided by @hainenber , it is now a windows-only problem. It works fine in WSL. It still is a problem.

Steps to reproduce

1. Clone my reproduction repo
2. run npm ci to install dependencies
3. run npm run test
4. Error comes up : "SyntaxError : Cannot use import statement outside a module"

Expected behavior

the package @vueuse/core should be transformed, according to the value of transformIgnorePatterns in jest.config.js.

Actual behavior

Jest fails with SyntaxError when importing @vueuse/core` It works in the other test when importing loadash

Additional context

I reproduces babel and jest configurations from the project I work on, but all with the latest versions.

Maybe related to issue #15728 ?

Environment

System:
   OS: Windows 11
Binairies:
   node: 22.16.0
   npm: 11.4.1
npmPackages:
   @babel/plugin-transform-runtime: 7.28.0
   @babel/preset-env: 7.28.0
   @babel/runtime-corejs3: 7.28.2
   @vueuse/core: 13.6.0
   babel-jest: 30.0.5
   jest-environment-jsdom: 30.0.5
   jest: 30.0.5
   lodash: 4.17.21

Also with the same npmPackages on WSL2

System:
   OS: 6.6.87.2-microsoft-standard-WSL2
Binairies:
   node: 22.18.0
   npm: 11.5.2

[byCedric]

Negative transform ignore patterns to force transforming files in node_modules is widely used inside React Native as well: https://github.com/facebook/react-native/blob/f936780cd5c0c17797f9d2bbc8f5cee81c2eefce/packages/react-native/jest-preset.js#L25-L27.

This is a major blocker for the whole React Native community migrating Jest to 30.

[malopgrics]

This is a major blocker for the whole React Native community migrating Jest to 30.

I experienced this bug with jest 29.5.14 too

[hainenber]

@malopgrics the whole transpilation was driving me crazy but I managed to fix your issue:

• Change your Babel config file to babel.config.json
• Add @babel/core as devDeps

The transformIgnorePatterns are still fine, no changes needed :D

Picture for confirmation (the test failed but at least it was due to something else, not due to lack of code transform)

@byCedric can you elaborate more on your case? My hunch is that it has something to do with Babel setup and config again but let's see how your case goes

[malopgrics]

Thank you for your input @hainenber .

I applied and pushed your suggestions to my reproduction repo.

Now it works_with WSL, but still not with Windows. I guess your setup is Linux or Mac ?

[hainenber]

Yes, my setup is on *nix. Haven't touched Windows machine for ages :D

What's your issue on Windows machine? I guess it starts to creep into platform-specific territory now ...

[malopgrics]

What's your issue on Windows machine?

With your suggestions applied, the result is the same on windows.

I'm currently trying to change the regexp to use path.sep:

import { sep } from 'node:path';

export default {
   // ....
   transformIgnorePatterns: [`${sep}node_modules${sep}(?!(\\@vueuse)${sep})`],
   // ...
};

But now it seems to fail in the transformation. Still a step forward.

EDIT :
It's trying to transpile core-js. I think the regular expression with path.sep cause all node modules to be transpiled. From another stacktrace, I noticed that jest already adapt the regex to replace / with \\ under windows. Other than that, I'm pretty stuck right now.