[Feature Request] Support new ESLint flat config

[TomerAberbach]

ESLint has a new experimental config file format and this plugin doesn't work with it. The plugin fails at this line because the new config format doesn't pass parsers via paths. Instead the parser object itself is passed.

I was able to mostly fix this in my fork, but because the parserPath doesn't exist anymore for this config format some of the keysFromParser logic won't work anymore.

Anyway, figured I'd open this issue to start discussion on the new config file format!

[ljharb]

If there's a way to support both configs at the same time, a PR would be appreciated.

Look to jsx-eslint/eslint-plugin-jsx-a11y#891 and jsx-eslint/eslint-plugin-react#3429 for some preferred direction.

[TomerAberbach]

Yup, my fork does support both configs. The only thing I'm unsure about in my fork is how to adapt the keysFromParser logic to work without knowing the paths.

But based on this comment though, it sounds like maybe it's fine for the new config format not to set visitorKeys to anything? Let me know!

[ljharb]

As long as the rules and configs work in both config systems, we're good.

[b0o]

The plugin fails at this line because the new config format doesn't pass parsers via paths.

We're experiencing this issue as well. @TomerAberbach it would be really cool if you could submit a PR with your fixes!

[TomerAberbach]

Thanks for the message! Been a bit busy with other stuff and kind of forgot about this 😅

I'll try to pick this up soon!

[goosewobbler]

As long as the rules and configs work in both config systems, we're good.

I'll test this on my fork of @TomerAberbach's fork when I get a chance.

[TomerAberbach]

Thanks @goosewobbler! A little while ago I tried making it so that all the tests get run twice (once with the legacy and once with the new config system), but got stuck trying to get stuff working and then got busy 🙃

Would be awesome if you're able to figure out how to test both systems! Happy to answer any questions about the fork if that would help as well

[CallMeLaNN]

I managed to make it work without changes in parser.js source. Since parserPath can be parser name and keysFromParser can accept it, we can use the settings.import/parsers to add the missing parser from getParserPath function.

So that can pass the parserPath is required! error but actually I don't see parserPath is useful to keysFromParser because on my env it always doesn't hit the line mentioned in keysFromParser logic won't work anymore. So "espree" below is the default I guess from the source.

This is my working test config on node and typescript env. (EDIT: I just remove from using FlatCompat and directly construct the config)

import importPlugin from "eslint-plugin-import";

export default [
  // ... "eslint:recommended"
  {
    // All eslint-plugin-import config is here
    languageOptions: {
      parserOptions: {
        // Eslint doesn't supply ecmaVersion in `parser.js` `context.parserOptions`
        // This is required to avoid ecmaVersion < 2015 error or 'import' / 'export' error
        ecmaVersion: "latest",
        sourceType: "module",
      },
    },
    plugins: { import: importPlugin },
    settings: {
      // This will do the trick
      "import/parsers": {
        espree: [".js", ".cjs", ".mjs", ".jsx"],
      },
      "import/resolver": {
        typescript: true,
        node: true,
      },
    },
    rules: {
      ...importPlugin.configs["recommended"].rules,
    },
  },
  // ... add other plugins like typescript-eslint etc
  {
    // All my custom config
    languageOptions: {
      // This default get replaced by plugins, so I added back. Not related probably.
      ecmaVersion: "latest",
      sourceType: "module",
     // ... globals etc
    },
  },
  // ... custom rules etc
]

It was discovered and tested on a module js file with import/namespace rule throw like this. I lint the eslint.config.js itself lol

Parse errors in imported module '@eslint/eslintrc': parserPath is required! (undefined:undefined) eslint(import/namespace)

[ziimakc]

Any way to make it work in meantime with flat config?

UPD. espree did the trick:

"import/parsers": {
    espree: [".js", ".cjs", ".mjs", ".jsx"],
    "@typescript-eslint/parser": [".ts"],
},