Change Request: Introduce Prettier

[lumirlumir]

Which packages would you like to change?

• espree
• eslint-scope
• eslint-visitor-keys

What problem do you want to solve?

Hi,

In this issue, I'd like to suggest adding Prettier as a code formatting tool for this repository.

Currently, the js repository doesn't have a dedicated formatter, unlike other repositories such as rewrite and eslint, which both use Prettier.

The absence of a formatter has caused some inconvenience for me, especially while working on #667.

Although we now have a formatting setup through the ESLint config, I don't think it's quite enough since it only applies to JavaScript. (Also, as far as I know, the modern approach is to separate linting and formatting logic.)

js/eslint.config.js

Line 3 in d777273

import eslintConfigESLintFormatting from "eslint-config-eslint/formatting";

So, in conclusion, I'd like to suggest adding Prettier to this repository.

What do you think is the correct solution?

I'll follow the configuration used throughout the ESLint repository, as shown below:

// prettier.config.js

export default {
	useTabs: true,
	tabWidth: 4,
	arrowParens: "avoid",

	overrides: [
		{
			files: ["*.json"],
			options: {
				tabWidth: 2,
				useTabs: false,
			},
		},
	],
};

Participation

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

Additional comments

No response

[nzakas]

Adding Prettier to an existing repo can be a bit challenging. See the discussion here:
eslint/eslint#17814

I'm not really sure it's worth the time and effort to do on this repo given the number of already open issues we could otherwise be spending time on.

[mdjermanovic]

We'll need to switch from the deprecated formatting rules we're currently using sooner or later as they won't be updated to support new syntaxes we'll likely use in the future, so I think it's fine to switch to Prettier now if we have time.

[JoshuaKGoldberg]

I'm pretty in favor of this 🙂 the longer a repo waits to enable a formatter, the more work it typically ends up being (by virtue of having more files and chances of rare edge cases).

Maybe it would make sense to have a kind of template repository specific to the ESLint organization for new repos like this one?

[mdjermanovic]

Just a note that I still support this proposal, but, if accepted, I think it should wait until all breaking PRs for ESLint v10 are merged, to avoid merge conflicts.

[lumirlumir]

TSC Summary: ESLint v11 is planning to drop support for formatting rules, so this PR seeks feedback on introducing Prettier as the dedicated formatter for the JS (eslint/js) repository. There is currently no definitive team consensus on this change.

TSC Questions:

1. Would it be acceptable to introduce Prettier into the JS (eslint/js) repository?
2. According to the comment(Change Request: Introduce Prettier #671 (comment)), when would be the best time to open a PR? Currently, only feat: add types to ESLint Scope #709 remains as part of the ESLint v10 changes.
3. The tsc-meetings repository has introduced Prettier in chore: introduce prettier tsc-meetings#641. Is there a plan to introduce Prettier to other repositories such as create-config or eslint-github-bot?