Environment

Node version: v23.1.0
npm version: v10.9.0
Local ESLint version: v9.20.0 (Currently used)
Global ESLint version: Not found
Operating System: darwin 24.2.0

What parser are you using?

Default (Espree)

What did you do?

Repro: https://github.com/brandongit2/eslint-jiti-bug-repro

Steps:

1. Clone the repository above
2. pnpm install in the cloned repo
3. pnpm lint to run ESLint
4. Error:
   

What did you expect to happen?

I expected the file to lint successfully.

What actually happened?

TypeError: Cannot read properties of undefined (reading 'configs')

Link to Minimal Reproducible Example

https://github.com/brandongit2/eslint-jiti-bug-repro

Participation

• I am willing to submit a pull request for this issue.

Additional comments

I was able to track down the issue to this line:

Setting interopDefault: true fixes the exception.

Reason for the exception:

1. eslint-plugin-react-compiler is a pure-CJS library
2. ESLint loads TypeScript configs with Jiti
3. Jiti uses @babel/plugin-transform-modules-commonjs during its Babel transform step
4. When your config-loader.js sets interopDefault: false, the Babel plugin turns off its importInterop setting which breaks the eslint-plugin-react-compiler import (info on the importInterop setting)
5. That Babel plugin rewrites all references to default imports. So when I do import reactCompiler from 'eslint-plugin-react-compiler', every reference to reactCompiler in the config becomes reactCompiler.default.
6. The .default property doesn't exist on that import, hence Cannot read properties of undefined (reading 'configs') when I try to access reactCompiler.configs.recommended.

This PR in the Jiti repo mentions how the interopDefault setting is important in many cases.