Eslint 8.0.1 - implementing jest into config throws an error

Question

In my Next/React/Typescript/Jest project I'm trying to configure my eslint config. After updating to version 8.x (currently 8.0.1), the linter throws following error:

Error: .eslintrc.js » ./eslint/config.js:
    Environment key "jest/globals" is unknown

Then I added 'plugin:jest/recommended' to the extends array in my config.js , which led me to this error:

TypeError: Failed to load plugin 'jest' declared in '.eslintrc.js » ./eslint/config.js': Class extends value undefined is not a constructor or null

The plugin is installed and inside my package.json . Even several npm ci haven't helped me here.

Would appreciate ideas !

Answer 1

Are you using any other eslint plugins? If so, has npm warned you of any peer dependency issues?

I ran into this same issue when upgrading to eslint v8.0.1. In may case, one plugin I listed an an earlier version of @typescript-eslint/eslint-plugin as a direct dependency ( @typescript-eslint/eslint-plugin is also a peer dependency of eslint-plugin-jest ). This earlier version of @typescript-eslint/eslint-plugin was not compatible with eslint v8.0.1. So I opted to downgrade to v7.32.0

If you have control over the other plugins you use, you might upgrade their dependencies and publish a new release. Else, you'll probably have to downgrade eslint in your project.