feat: support eslint.config.js

[aladdin-add]

fixes #89

an example:

const nodeRecommended = require("eslint-plugin-n/configs/recommended")
module.exports = [
    nodeRecommended,
    {
        rules: {
            "n/exports-style": ["error", "module.exports"]
        }
    }
]

[voxpelli]

Isn't this feature still very much a work in progress in ESLint core?

The official docs (https://eslint.org/docs/latest/use/configure/configuration-files-new) say:

This config system is feature complete but not enabled by default. To opt-in, place an eslint.config.js file in the root of your project or set the ESLINT_USE_FLAT_CONFIG environment variable to true.

What are the implications of this change?

[voxpelli]

Noticed EvgenyOrekhov/eslint-config-hardcore#726 when I scrolled further in my notifications and now I think I have missed an announcement on the ESLint blog or something 🙈

[voxpelli]

And now I noticed #89 as well

Would have been great to have a link to that in the description, and if done using the "fixes #89" wording then that issue would be automatically closed when this PR is merged 🙂

[aladdin-add]

@voxpelli I've mentioned the issue in the commit: 3830d3e, but forgot to add it in the PR desc. 😂

updated.

[mdjermanovic]

Thanks for working on this! Yes, since we've finished Phase 2 (eslint/eslint#13481) it's time for plugins to start adding support for the new config system, and in Phase 3 we have this task for this particular plugin.

[mdjermanovic]

It would be nice to add metadata:

https://eslint.org/docs/latest/extend/plugins#metadata-in-plugins

[aladdin-add]

👍 pushed a commit: 33045c6. 😏

[aladdin-add]

ptla :). cc @mdjermanovic

[mdjermanovic]

Missing sourceType?

[mdjermanovic]

I'm actually not sure if there should be recommended config because it would be wrong for .cjs/.mjs files. The current eslintrc config has overrides for them, so it works well. We could do something similar here - export an array of configs with the files key - but that should generally be avoided in the new config system because it makes the config more difficult to manipulate with (e.g., to apply it to a specific directory only).

For commonjs projects, user's config should typically be:

// user's eslint.config.js

const nodeRecommendedScript = require("eslint-plugin-n/configs/recommended-script");
const nodeRecommendedModule = require("eslint-plugin-n/configs/recommended-module");

module.exports = [
    {
        files: ["**/*.js", "**/*.cjs"],
        ...nodeRecommendedScript
    },
    {
        files: ["**/*.mjs"],
        ...nodeRecommendedModule
    }
]

For "type": "module" projects:

// user's eslint.config.js

import nodeRecommendedScript from "eslint-plugin-n/configs/recommended-script.js";
import nodeRecommendedModule from "eslint-plugin-n/configs/recommended-module.js";

export default [
    {
        files: ["**/*.js", "**/*.mjs"],
        ...nodeRecommendedModule
    },
    {
        files: ["**/*.cjs"],
        ...nodeRecommendedScript
    }
];

What do you think?

[aladdin-add]

In the beginning, to minimize the difference with the eslintrc presets, I had wondered if a configuration could be provided:

module.exports = packageJson.type === "module" ? moduleConfig : scriptConfig;

but it won't work well if it's using with ".cjs" and ".mjs". /_ \

Yes, this way sounds much clearer. Will remove it and document the usage. Thanks for the thoughtful feedback! ❤️

[mdjermanovic]

LGTM, thanks! I left only some minor notes.

[mdjermanovic]

Compared to the previous version, this will now lint test/fixtures too, so just to check if that's intentional?

[mdjermanovic]

Compared to the previous (.eslintrc.js) config, this one might be missing this rule:

eslint-plugin-n/.eslintrc.js

Lines 20 to 22 in bea9981

	rules: {
	"eslint-plugin/require-meta-docs-description": "error",
	},

[mdjermanovic]

Maybe there should also be an example with configs/recommended-module, for ESM ("type": "module") projects?