chore: remove .eslintrc.js

[aladdin-add]

note: it's not to remove eslintrc support.

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofix to a rule
[ ] Add a CLI option
[ ] Add something to the core
[x] Other, please explain:

What changes did you make? (Give an overview)

Is there anything you'd like reviewers to focus on?

• .eslintignore was not removed, as it was used in a test:

  eslint/tests/lib/cli-engine/file-enumerator.js

  Lines 459 to 467 in 38b9b06

  	it("should throw an error if no files match a glob", () => {
  	// Relying here on the .eslintignore from the repo root
  	const patterns = ["tests/fixtures/glob-util/ignored/**/*.js"];
  	assert.throws(() => {
  	listFiles(patterns);
  	}, `All files matched by '${patterns[0]}' are ignored.`);
  	});

• do we need to add .vscode (as the flat config not enabled by default in vscode-eslint)?

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[nzakas]

Can you update the description of this PR with an explanation of what changes you made? It's not clear from the title what the intent of this PR is.

[aladdin-add]

The ESLint repository currently contains two ESLint configurations: eslint.config.js (used by npm run lint) and .eslintrc.js (used by vscode-eslint). With the recent support for flat configuration in vscode-eslint, you can enable it by setting "eslint.experimental.useFlatConfig": true. Therefore, this pr removes '.eslintrc.js' and adds the configuration for vscode-eslint.

[aladdin-add]

Coverting to a draft, as I think it's better to refactor the test to not relying on the.eslintignore in root dir.

[mdjermanovic]

Coverting to a draft, as I think it's better to refactor the test to not relying on the.eslintignore in root dir.

I think it's fine to leave .eslintignore for now. Some 150-200 tests are using this file, so we'll need to check each before removing this file.

[nzakas]

The ESLint repository currently contains two ESLint configurations: eslint.config.js (used by npm run lint) and .eslintrc.js (used by vscode-eslint). With the recent support for flat configuration in vscode-eslint, you can enable it by setting "eslint.experimental.useFlatConfig": true. Therefore, this pr removes '.eslintrc.js' and adds the configuration for vscode-eslint.

It seems like we're at the point where we should be pushing VS Code to enable flat config by default? Potentially by using shouldUseFlatConfig()? I'd much rather do that then start incorporating VS Code settings into the repo (which we'll need to change later).

[aladdin-add]

@nzakas there is a discussion: microsoft/vscode-eslint#1644

[aladdin-add]

I think it's fine to leave .eslintignore for now. Some 150-200 tests are using this file, so we'll need to check each before removing this file.

it seems the ci is happy when removing .eslintignore(13daf5e), am i missing something? 🤔 @mdjermanovic

[mdjermanovic]

it seems the ci is happy when removing .eslintignore(13daf5e), am i missing something?

A test might still be passing but not actually testing what it was intended to if the assertions aren't precise enough. Now, that might not be the case for those particular tests, but it would be good to check each at some point.

[aladdin-add]

well, will remove the commit.

[JoshuaKGoldberg]

Exciting!

[JoshuaKGoldberg]

[Question] Is there any reason to keep this around? Since .vscode/settings.json is now intentional:

Suggested change

# /.vscode

[JoshuaKGoldberg]

do we need to add .vscode (as the flat config not enabled by default in vscode-eslint)?

Linking for reference: microsoft/vscode-eslint#1644

Looks like, yes for now?

[nzakas]

I'd still rather wait so we don't have to do this.
#18075

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[Rec0iL99]

Not stale. Waiting for #18075 to resolve.

#18011 (comment) for reference.

[mdjermanovic]

So, we're waiting here for vscode-eslint v3, which will by default detect and use flat config. The last prerelease (https://github.com/microsoft/vscode-eslint/releases/tag/3.0.5-alpha.1) was about month ago and it's still alpha, so the final release might not be that soon.

@aladdin-add what do you think about splitting this PR into two PRs:

1. Remove eslintrc from eslint-config-eslint
   • Copy & paste the content of packages/eslint-config-eslint/eslintrc.js into root .eslintrc.js.
   • Remove packages/eslint-config-eslint/eslintrc.js and its export from packages/eslint-config-eslint/package.json.
2. Remove root .eslintrc.js and dev dependencies from the root package.json.

We could merge (1) as soon as it's ready, and then release eslint-config-eslint v10 to unblock eslint/generator-eslint#179 and switch to ESLint v9 in all our projects. Only (2) would wait for vscode-eslint.

[mdjermanovic]

Here's (1): #18400

[aladdin-add]

#18400 has been merged, I resubmitted the (2).

[mdjermanovic]

LGTM, thanks! Just waiting for vscode-eslint v3.