Change Request: Provide a `definePlugin` function in `@eslint/plugin-kit`

[JoshuaKGoldberg]

Which packages would you like to change?

• @eslint/compat
• @eslint/config-array
• @eslint/config-helpers
• @eslint/core
• @eslint/migrate-config
• @eslint/object-schema
• @eslint/plugin-kit

What problem do you want to solve?

Right now, there's no standard factory function for writing ESLint plugins. https://eslint.org/docs/latest/extend/plugins provides suggested starting objects but:

• It's easy to mistype, forget fields, etc. in plain objects
• Having a factory function makes it easier to give types-directed suggestions in editors and type checking
• The function could abstract away the -IMO confusing- computed get()er and/or Object.assign folks have to do to get circular references working in the objects
• It could also apply common patterns and/or optimizations for users so they don't have to:
  • Common pattern: generating configs based on meta.docs.recommended or other properties
  • Optimizations: Enhancement: Support Lazy Loading Rules typescript-eslint/typescript-eslint#11029

What do you think is the correct solution?

How about an @eslint/plugin-utils package with a definePlugin export?

import { definePlugin } from "@eslint/plugin-utils";

export default definePlugin({
	meta: {
		name: "eslint-plugin-example",
		version: "1.2.3",
	},
	rules: {
		"dollar-sign": {
			meta: {
				docs: {
					recommended: true,
				}
			},
			create(context) {
				// rule implementation ...
			},
		},
	},
});

That meta.docs.recommended could be used to generate a configs.recommended in the standard format(s) preferred by flat config.

Participation

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

Additional comments

@eslint/plugin-kit exists but it's really more of a "languages" kit. I separately tried searching plugin-kit, plugin-utils, and similar terms on ESLint's issue trackers. The closest mention I could find was eslint/eslint#4301 (comment). I have a vague memory of this being discussed somewhere previously, but can't remember where...?

I'd be happy to write up an RFC if it's a direction the project would be interested in.

[nzakas]

Thanks for the suggestion. I neutral to a definePlugin() function, so happy to go along with consensus.

If people want it, then I do think it should go in @eslint/plugin-kit as I don't see why we'd make folks install two different dependencies to deal with two different parts of building a plugin.

cc @eslint/eslint-team

[fasttime]

• Having a factory function makes it easier to give types-directed suggestions in editors and type checking
• The function could abstract away the -IMO confusing- computed get()er and/or Object.assign folks have to do to get circular references working in the objects
• It could also apply common patterns and/or optimizations for users so they don't have to:
  • Common pattern: generating configs based on meta.docs.recommended or other properties
  • Optimizations: Enhancement: Support Lazy Loading Rules typescript-eslint/typescript-eslint#11029

I think these are all good points. I'd be in favor of adding a definePlugin() function to @eslint/plugin-kit.

[nzakas]

After giving this some more thought, I'm now 👍 to adding definePlugin to @eslint/plugin-kit. I think we should put this through an RFC to make sure we cover all of our bases.