feat: add types to ESLint Scope #709

fasttime · 2025-11-20T15:43:09Z

Prerequisites checklist

I have read the contributing guidelines.

What is the purpose of this pull request?

Add built-in types to ESLint Scope

What changes did you make? (Give an overview)

Copied and updated types and tests from DefinitelyTyped
- Added addGlobals() to ScopeManager
- Marked globalScope in ScopeManager as nullable
- Moved implicit from Scope to GlobalScope and added implicit.variables
- Added missing Scope subclasses
- Added @deprecated tag to deprecated members per https://github.com/eslint/eslint/blob/v10.0.0-alpha.0/docs/src/extend/scope-manager-interface.md
- Restricted functionExpressionScope to true or false depending on whether the Scope is FunctionExpressionNameScope
- Fixed resolve() in Scope (the definition in @types/eslint-scope is very different, possibly unrelated)
- Fixed several inconsistencies in PatternVisitor
Enabled type checking for source files in packages/eslint-scope/lib to verify they match the type declarations
Added npm scripts to test types
Added "Are the types wrong?" CI job
Linting *.ts and *.cts files
Minor fixes in the logic:
- Reference#isStatic() now always returns a boolean even when resolved is not set
- ScopeManager#isImpliedStrict() now always returns a boolean even when the impliedStrict option is not set

Related Issues

fixes #708

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

fasttime · 2025-11-20T22:25:13Z

packages/eslint-scope/lib/index.d.cts

+/**
+ * @fileoverview This file contains the types for ESLint Scope.
+ * It was initially extracted from the DefinitelyTyped repository.
+ */


Adapting the DefinitelyTyped types should be fine in terms of licensing, although I think it doesn't quite align with this project's guidelines:

js/packages/eslint-scope/CONTRIBUTING.md

Line 3 in 2ecfb8b

- You will only Submit Contributions where You have authored 100% of the content.

Copilot

Pull request overview

This PR adds built-in TypeScript type definitions to the ESLint Scope package, eliminating the need for separate @types/eslint-scope packages. The types were adapted from DefinitelyTyped with enhancements including nullable global scope, additional scope subclasses, deprecated member tags, and improved type safety through type checking of JavaScript source files.

Key changes:

Added TypeScript declaration files (index.d.ts, index.d.cts) with comprehensive type definitions
Enabled type checking for JavaScript source files using JSDoc annotations
Added type testing infrastructure with npm scripts and CI workflow

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/eslint-scope/tsconfig.json	TypeScript configuration for type-checking JavaScript source files
packages/eslint-scope/tests/types/tsconfig.json	TypeScript configuration for type test files
packages/eslint-scope/tests/types/types.test.ts	Comprehensive type tests covering all exported APIs
packages/eslint-scope/tests/types/cjs-import.test.cts	CommonJS import type test
packages/eslint-scope/package.json	Added type exports, dependencies, and scripts
packages/eslint-scope/lib/*.js	Added JSDoc type annotations to source files
packages/eslint-scope/lib/index.d.ts	ESM type declaration file (re-exports from .cts)
packages/eslint-scope/lib/index.d.cts	Main CommonJS type declaration file
eslint.config.js	Added TypeScript file linting configuration
package.json	Added TypeScript parser and expect-type plugin
.github/workflows/ci.yml	Added "Are the types wrong?" CI job

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packages/eslint-scope/tsconfig.json

packages/eslint-scope/tests/types/tsconfig.json

packages/eslint-scope/package.json

packages/eslint-scope/tests/types/cjs-import.test.cts

mdjermanovic · 2025-11-25T16:34:22Z

packages/eslint-scope/lib/index.d.cts

+    /**
+     * The identifier node of the reference.
+     */
+    identifier: ESTree.Identifier;


This can also be JSXIdentifier.

It's true, but we need to update the base interface Scope.Reference in ESLint first, because we can't broaden the type of the identifier member in the implementing class.

js/packages/eslint-scope/lib/index.d.cts

Line 568 in c6d38b2

export class Reference implements eslint.Scope.Reference {

packages/eslint-scope/lib/index.d.cts

github-actions · 2025-12-07T22:34:28Z

Hi everyone, it looks like we lost track of this pull request. Please review and see what the next steps are. This pull request will auto-close in 7 days without an update.

lumirlumir

This looks like a good start!

I've left some comments throughout, especially regarding documentation updates.

.github/workflows/ci.yml

lumirlumir · 2025-12-08T08:38:30Z

packages/eslint-scope/package.json

+    "@arethetypeswrong/cli": "^0.18.2",
    "@typescript-eslint/parser": "^8.7.0",
    "chai": "^6.0.0",
+    "eslint": ">=10.0.0-alpha.0 <10.0.0 || ^10.0.0",


Suggested change

"eslint": ">=10.0.0-alpha.0 <10.0.0 || ^10.0.0",

"eslint": ">=10.0.0-alpha.0 <10.0.0 || ^10.0.1",

It seems that @eslint/[email protected] was released accidentally, so perhaps eslint should also start at 10.0.1 instead of 10.0.0?

References:

https://github.com/eslint/eslint/blob/main/packages/eslint-config-eslint/package.json#L66

chore: update eslint-config-eslint dependencies for v10 prereleases eslint#20278 (comment)

We no longer need to keep the version numbers of eslint and @eslint/js in sync. In fact, eslint no longer depends on @eslint/js. See also https://github.com/eslint/tsc-meetings/blob/main/notes/2025/2025-11-13.md#should-we-continue-releasing-eslintjs-every-time-we-release-eslint. The next stable ESLint release will be v10.0.0.

packages/eslint-scope/lib/index.d.cts

lumirlumir · 2025-12-08T10:14:08Z

packages/eslint-scope/lib/index.d.cts

+/**
+ * Represents a variable in a scope.
+ */
+export class Variable<TReference extends Reference = Reference> {


Question: there are some static properties like the following:

Should these types also be applied to the Variable class?

js/packages/eslint-scope/lib/variable.js

Lines 77 to 83 in 26eb6e2

Variable.CatchClause = "CatchClause";

Variable.Parameter = "Parameter";

Variable.FunctionName = "FunctionName";

Variable.ClassName = "ClassName";

Variable.Variable = "Variable";

Variable.ImportBinding = "ImportBinding";

Variable.ImplicitGlobalVariable = "ImplicitGlobalVariable";

Good question. These are the possible values for the type property of aDefinition. These constants aren't documented, but neither are the constructor signatures for Scope, Variable, Definition, etc, which all have their type definitions. I'd say it's fine to add types in this case, but I don't feel strongly.

lumirlumir · 2025-12-08T10:18:18Z

packages/eslint-scope/lib/index.d.cts

+/**
+ * Represents a reference to a variable.
+ */
+export class Reference {


Question: there are also some static properties like the following:

Should these types also be applied to the Reference class?

js/packages/eslint-scope/lib/reference.js

Lines 146 to 162 in 26eb6e2

/**

* @constant Reference.READ

* @private

*/

Reference.READ = READ;

/**

* @constant Reference.WRITE

* @private

*/

Reference.WRITE = WRITE;

/**

* @constant Reference.RW

* @private

*/

Reference.RW = RW;

As with the previous question, these values are undocumented, so I don't feel strongly whether they should be included in the types or not.

Co-authored-by: 루밀LuMir <[email protected]>

packages/eslint-scope/lib/index.d.cts

fasttime · 2025-12-09T20:14:55Z

Okay, I think I've addressed all the feedback now.

feat: add types to ESLint Scope

9acbf0d

github-project-automation bot added this to Triage Nov 20, 2025

github-project-automation bot moved this to Needs Triage in Triage Nov 20, 2025

eslint-github-bot bot added the feature label Nov 20, 2025

eslint-github-bot bot mentioned this pull request Nov 20, 2025

Change Request: update eslint-scope types #708

Open

4 tasks

fasttime added 2 commits November 21, 2025 08:26

fallback to .d.cts types

ec36239

add missing scopes

2d40e1d

nzakas moved this from Needs Triage to Implementing in Triage Nov 21, 2025

fasttime added 5 commits November 21, 2025 15:48

add deprecations

96febf0

fixes

b23b18f

fix tests

2a3962c

more fixes

951db73

type check source files

095c33a

fasttime commented Nov 25, 2025

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fasttime requested a review from Copilot November 25, 2025 10:45

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fasttime added 2 commits November 25, 2025 11:59

make sure to use the latest versions of type dependencies

8a79929

explain unused imports

c6d38b2

fasttime marked this pull request as ready for review November 25, 2025 11:06

mdjermanovic reviewed Nov 25, 2025

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mdjermanovic mentioned this pull request Nov 25, 2025

feat!: enable JSX reference tracking eslint/eslint#20152

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mdjermanovic reviewed Nov 26, 2025

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packages/eslint-scope/lib/index.d.cts Outdated Show resolved Hide resolved

remove dependency on eslint types

3658660

fasttime mentioned this pull request Nov 30, 2025

feat: TypeScript support for Espree #705

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1 task

github-actions bot added the Stale label Dec 7, 2025

lumirlumir added accepted and removed Stale labels Dec 8, 2025

lumirlumir requested changes Dec 8, 2025

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fasttime and others added 4 commits December 8, 2025 20:45

Apply suggestions from code review

5d71f52

Co-authored-by: 루밀LuMir <[email protected]>

Update packages/eslint-scope/lib/index.d.cts

59f655a

Co-authored-by: 루밀LuMir <[email protected]>

update readme file

6bb4d2e

update type parameter of Scope constructor

f0ceaf6

fasttime commented Dec 9, 2025

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packages/eslint-scope/lib/index.d.cts Outdated Show resolved Hide resolved

Update packages/eslint-scope/lib/index.d.cts

01bd9aa

fasttime requested a review from lumirlumir December 9, 2025 20:14

lumirlumir mentioned this pull request Dec 10, 2025

chore: update @eslint/core, add legacy-peer-deps, and use ESLint v10 eslint/json#190

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1 task

	"eslint": ">=10.0.0-alpha.0 <10.0.0 \|\| ^10.0.0",
	"eslint": ">=10.0.0-alpha.0 <10.0.0 \|\| ^10.0.1",

	Variable.CatchClause = "CatchClause";
	Variable.Parameter = "Parameter";
	Variable.FunctionName = "FunctionName";
	Variable.ClassName = "ClassName";
	Variable.Variable = "Variable";
	Variable.ImportBinding = "ImportBinding";
	Variable.ImplicitGlobalVariable = "ImplicitGlobalVariable";

	/**
	* @constant Reference.READ
	* @private
	*/
	Reference.READ = READ;

	/**
	* @constant Reference.WRITE
	* @private
	*/
	Reference.WRITE = WRITE;

	/**
	* @constant Reference.RW
	* @private
	*/
	Reference.RW = RW;

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fasttime commented Dec 9, 2025

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fasttime commented Nov 20, 2025 •

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