feat: TypeScript support for Espree by brettz9 · Pull Request #705 · eslint/js

brettz9 · 2025-10-27T12:06:33Z

Prerequisites checklist

I have read the contributing guidelines.

What is the purpose of this pull request?

Provide TypeScript support for espree.

What changes did you make? (Give an overview)

applied checkJs/allowJs TypeScript to espree.
complete test coverage
in lib/espree.js, removes an uncovered and apparently unnecessary branch (previously lines 152-154) where a property was being added to an array.

Related Issues

A renewed approach to #544 which doesn't require a special, fragile build routine or non-standard JSDoc tags.

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

The @typedef exports that were of previous concern should not be here since the main file does not use them except for public type exports. Otherwise, we are using @import.

Has some added complexity in redefining Acorn/acorn-jsx because Acorn's TypeScript does not concern all properties of relevance to plugin authors. See acornjs/acorn#1404 .

Currently applies acorn-jsx from my own fork as waiting on acornjs/acorn-jsx#139 .

github-actions · 2025-11-09T22:33:55Z

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.

fasttime · 2025-11-10T17:37:00Z

Not stale. This PR needs to be reviewed.

nzakas · 2025-11-11T15:52:15Z

@brettz9 thanks for this. We're in the middle of preparing to release the first prerelease of v10, so we're a bit swamped at the moment. We'll get around to reviewing this once our schedules free up a bit.

github-actions · 2025-11-21T22:35:14Z

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.

fasttime · 2025-11-30T19:30:30Z

I think this is a very good approach to autogenerating the types. We could adopt some of these techniques in other repositories to simplify complexity.

brettz9 · 2025-11-30T19:50:01Z

I think this is a very good approach to autogenerating the types. We could adopt some of these techniques in other repositories to simplify complexity.

Great... If you end up using this approach, I have a branch ready for eslint-scope as well (though it looks like you might already be working on one, sorry!).

fasttime · 2025-11-30T20:10:31Z

I think this is a very good approach to autogenerating the types. We could adopt some of these techniques in other repositories to simplify complexity.

Great... If you end up using this approach, I have a branch ready for eslint-scope as well (though it looks like you might already be working on one, sorry!).

We can definitely look into autogenerating types for eslint-scope as well if we can maintain compatibility with the current types in @types/eslint-scope. I'd suggest doing that in a separate pull request once #709 is merged in order to avoid overlaps.

fasttime

Since espree types are a new feature, what do you think about adding tests for it? We already have type tests for eslint-visitor-keys in packages/eslint-visitor-keys/test-d/index.test-d.ts and we could add similar tests for espree as well. DefinitelyTyped also has type tests for @types/espree which could be a useful reference, if we want to build on their work.

packages/espree/package.json

packages/espree/espree.js

packages/espree/lib/token-translator.js

brettz9 · 2025-12-01T02:19:43Z

Since espree types are a new feature, what do you think about adding tests for it?

Sure.

We already have type tests for eslint-visitor-keys in packages/eslint-visitor-keys/test-d/index.test-d.ts and we could add similar tests for espree as well. DefinitelyTyped also has type tests for @types/espree which could be a useful reference, if we want to build on their work.

That was a helpful pattern to follow. I've added a1d2f7a which adds their tests as well as 138f496 which adds the public exports they were missing. Let me know if you think we need coverage for other types (and which ones).

fasttime · 2025-12-01T13:15:26Z

We already have type tests for eslint-visitor-keys in packages/eslint-visitor-keys/test-d/index.test-d.ts and we could add similar tests for espree as well. DefinitelyTyped also has type tests for @types/espree which could be a useful reference, if we want to build on their work.

That was a helpful pattern to follow. I've added a1d2f7a which adds their tests as well as 138f496 which adds the public exports they were missing. Let me know if you think we need coverage for other types (and which ones).

I think that's good enough for a start.

Co-authored-by: 루밀LuMir <rpfos@naver.com>

Co-authored-by: Francesco Trotta <github@fasttime.org>

fasttime

LGTM, thanks!

github-project-automation bot added this to Triage Oct 27, 2025

eslint-github-bot bot added the feature label Oct 27, 2025

github-project-automation bot moved this to Needs Triage in Triage Oct 27, 2025

brettz9 force-pushed the types branch 7 times, most recently from 72bc186 to 7564529 Compare October 29, 2025 05:24

lumirlumir requested a review from a team October 30, 2025 08:35

github-actions bot added the Stale label Nov 9, 2025

brettz9 force-pushed the types branch from 7564529 to 58cc8f8 Compare November 10, 2025 17:25

fasttime removed the Stale label Nov 10, 2025

github-actions bot added the Stale label Nov 21, 2025

fasttime removed the Stale label Nov 21, 2025

fasttime moved this from Needs Triage to Triaging in Triage Nov 30, 2025

fasttime moved this from Triaging to Implementing in Triage Nov 30, 2025

fasttime added the accepted label Nov 30, 2025

fasttime reviewed Nov 30, 2025

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fasttime added the contributor pool label Nov 30, 2025

brettz9 and others added 22 commits December 29, 2025 22:24

remove dist/lib with evaluated script

d73b6b0

revert to stable acorn-jsx

8a72a35

inline acorn-jsx types

281e211

Update packages/espree/lib/espree.js

a12f55f

Co-authored-by: 루밀LuMir <rpfos@naver.com>

switch from Integer to number

1ee7bbf

liberalize version

6c50b1b

Update packages/espree/tsconfig.json

942c70b

Co-authored-by: 루밀LuMir <rpfos@naver.com>

Update packages/espree/tsconfig-cjs.json

9188d5d

Co-authored-by: 루밀LuMir <rpfos@naver.com>

use bare import specifier

1f834d5

set getLatestEcmaVersion to last const value in union

277b720

narrow parse return type to acorn.Program

50565bc

reuse existing import for types

7b20583

double quotes

81bca5f

Update packages/espree/lib/espree.js

46ff304

Co-authored-by: 루밀LuMir <rpfos@naver.com>

Update packages/espree/espree.js

a664f3f

Co-authored-by: 루밀LuMir <rpfos@naver.com>

Update packages/espree/lib/options.js

8cd7135

Co-authored-by: 루밀LuMir <rpfos@naver.com>

use @import

33ac707

Update packages/espree/espree.js

2d9e38a

Co-authored-by: 루밀LuMir <rpfos@naver.com>

normalizedEcmaVersion -> NormalizedEcmaVersion

edf4744

infer _R -> unknown[]

2b9725d

Co-authored-by: Francesco Trotta <github@fasttime.org>

move JSDoc types after imports

d4a27f9

use EcmaVersion internally to options.js function

bcef526

brettz9 force-pushed the types branch from 670d0d9 to bcef526 Compare December 30, 2025 05:24

revert EcmaVersion values and add need for updating to CONTRIBUTING

e58590e

fasttime approved these changes Dec 30, 2025

View reviewed changes

fasttime merged commit 5887c4d into eslint:main Dec 30, 2025
15 checks passed

github-project-automation bot moved this from Second Review Needed to Complete in Triage Dec 30, 2025

eslintbot mentioned this pull request Dec 30, 2025

chore: release main #718

Merged

brettz9 deleted the types branch December 30, 2025 12:46

mdjermanovic mentioned this pull request Jan 18, 2026

fix: restore comments property on tokenize() return value #721

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Prerequisites checklist

What is the purpose of this pull request?

What changes did you make? (Give an overview)

Related Issues

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

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github-actions bot commented Nov 9, 2025

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fasttime commented Nov 10, 2025

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nzakas commented Nov 11, 2025

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brettz9 commented Dec 1, 2025

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brettz9 commented Oct 27, 2025 •

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