Support ESLint "flat" configs

[michaelfaith]

I searched through the issues for something similar, and didn't find anything related to supporting the new Flat Config. So I thought it would make sense to create this for tracking.

I'm currently building out a config using eslint.config.js and the new flat config structure. When using this plugin, I receive the following error:

TypeError: Key "plugins": Key "0": Expected an object.
    at Object.validate (D:\src\ux\.yarn\cache\eslint-npm-8.45.0-bb6c5f1226-3e6dcce5cc.zip\node_modules\eslint\lib\config\flat-config-schema.js:315:23)
    at ObjectSchema.validate (D:\src\ux\.yarn\cache\@humanwhocodes-object-schema-npm-1.2.1-43b3ca2646-a824a1ec31.zip\node_modules\@humanwhocodes\object-schema\src\object-schema.js:218:35)
    at D:\src\ux\.yarn\cache\@humanwhocodes-object-schema-npm-1.2.1-43b3ca2646-a824a1ec31.zip\node_modules\@humanwhocodes\object-schema\src\object-schema.js:171:18
    at Array.reduce (<anonymous>)
    at ObjectSchema.merge (D:\src\ux\.yarn\cache\@humanwhocodes-object-schema-npm-1.2.1-43b3ca2646-a824a1ec31.zip\node_modules\@humanwhocodes\object-schema\src\object-schema.js:169:24)
    at D:\src\ux\.yarn\cache\@humanwhocodes-config-array-npm-0.11.10-33012f902e-1b1302e240.zip\node_modules\@humanwhocodes\config-array\api.js:916:42
    at Array.reduce (<anonymous>)
    at FlatConfigArray.getConfig (D:\src\ux\.yarn\cache\@humanwhocodes-config-array-npm-0.11.10-33012f902e-1b1302e240.zip\node_modules\@humanwhocodes\config-array\api.js:915:39)
    at FlatConfigArray.isFileIgnored (D:\src\ux\.yarn\cache\@humanwhocodes-config-array-npm-0.11.10-33012f902e-1b1302e240.zip\node_modules\@humanwhocodes\config-array\api.js:943:15)
    at D:\src\ux\.yarn\cache\eslint-npm-8.45.0-bb6c5f1226-3e6dcce5cc.zip\node_modules\eslint\lib\eslint\eslint-helpers.js:312:49

This is due to the fact that the shareable config defines plugins as a string array, rather than object:

eslint-plugin-jest/src/index.ts

Lines 52 to 56 in 0b7c3e5

	const createConfig = (rules: Record<string, TSESLint.Linter.RuleLevel>) => ({
	plugins: ['jest'],
	env: { 'jest/globals': true },
	rules,
	});

I'm able to work around it by constructing the config manually using the recommended rules:

import jest from 'eslint-plugin-jest';
import globals from 'globals';

export default [
  {
    plugins: { jest },
    rules: {
      ...jest.configs.recommended.rules,
    },
    languageOptions: {
      globals: {
        ...globals.jest,
      }
    }
  },
];

The eslint-plugin-react and eslint-plugin-jsdoc projects have updated to support this new config approach, if that helps with providing inspiration / examples.

[G-Rath]

Yeah we've had #1245 open implementing support, but everytime I sit down to try to make sense of the new flat config the docs always seem to be missing parts (and it is still actively being worked on) - as you've said it's pretty easy to work around for now.

Having said that it's been a while since I last looked at it, so I'll bump it up my todo list to try have another go next month.

[morganney]

The new flat config docs are definitely missing parts, which is not helping the transition to the new flat config approach. The docs should be in line with the running code.

[michaelfaith]

Having said that it's been a while since I last looked at it, so I'll bump it up my todo list to try have another go next month.

Appreciate it! If there's anything I can do to help with testing / validation / etc, let me know.

[michaelfaith]

The new flat config docs are definitely missing parts, which is not helping the transition to the new flat config approach. The docs should be in line with the running code.

I've found this doc to be pretty solid for end-user usage. But to your point, for plugin authors it could use some work.

[pauliesnug]

@G-Rath This would be amazing to have, also would necesitate generating d.ts files upon build.

[SimenB]

Alpha for v9 is out, it's probably time to implement support: https://github.com/eslint/eslint/releases/tag/v9.0.0-alpha.0

[G-Rath]

I've created #1503 for adding flat config support - I'd appreciate folks trying it out (though might be better to do so near the end of the week once I've had a chance to update it with the latest v9 changes😅)

Also fwiw it looks like there's now a FlatCompat class to help with migration.

[github-actions]

🎉 This issue has been resolved in version 27.9.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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