Introduce ES2025 target & Add missing ScriptTargetFeatures by petamoriken · Pull Request #63046 · microsoft/TypeScript

petamoriken · 2026-01-24T19:32:06Z

Fixes #61735

This PR includes the addition of 2 type files:

es2025.regexp.d.ts
es2025.intl.d.ts

Related issues and (stalled) PRs

ES2025 `RegExp.escape` (es2025.regexp.d.ts)

Closes #61321
Closes #62138

ES2025 `Intl.DurationFormat` (es2025.intl.d.ts)

Closes #60608
Closes #60646

typescript-bot · 2026-01-24T19:32:17Z

Thanks for the PR! It looks like you've changed the TSServer protocol in some way. Please ensure that any changes here don't break consumers of the current TSServer API. For some extra review, we'll ping @sheetalkamat, @mjbvz, and @joj for you. Feel free to loop in other consumers/maintainers if necessary.

typescript-bot · 2026-01-24T19:32:19Z

Looks like you're introducing a change to the public API surface area. If this includes breaking changes, please document them on our wiki's API Breaking Changes page.

Also, please make sure @DanielRosenwasser and @RyanCavanaugh are aware of the changes, just as a heads up.

pluma · 2026-01-28T18:49:17Z

Can we please get this reviewed? I know the country is burning and everyone is being replaced by AI but this would be really useful for those of us who deal with audiences across different languages.

jakebailey · 2026-01-28T21:07:57Z

We have a lot of these lib related PRs; it's absolutely our intention to review all of them as soon as we can, we've just had a bunch of other stuff that has been a bit more pressing.

jakebailey · 2026-01-28T21:09:40Z

I will note that an all-up PR for this may not be as useful as us reviewing the individual esnext PRs and then having a dedicated ES2025 PR; them being mixed together in this PR is making it hard to figure out what's new and what's just moving around. I would have preferred that the other PRs not be closed and this PR be a pure move + define options.

petamoriken · 2026-01-28T21:24:58Z

Only two files were newly added: es2025.intl.d.ts and es2025.regexp.d.ts.

I created this combined PR because the individual "esnext" PRs for these features had stalled, and there had been no progress. I wanted to take over the tasks myself, and since there are only two added files, I thought the review would not be too difficult.

@jakebailey If you still prefer to have them separated, I can create two individual PRs instead. What do you think?

Co-authored-by: lionel-rowe <lionel.rowe@gmail.com>

Co-authored-by: 김상두 <puki4416@gmail.com>

petamoriken · 2026-02-01T12:22:29Z

@jakebailey For now, I can remove the additions of es2025.intl.d.ts and es2025.regexp.d.ts from this PR, but should I do so? Please let me know your thoughts.

jakebailey · 2026-02-04T19:11:03Z

@typescript-bot test it

typescript-bot · 2026-02-04T19:11:08Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`test top400`	✅ Started	✅ Results
`user test this`	✅ Started	✅ Results
`run dt`	✅ Started	✅ Results
`perf test this faster`	✅ Started	👀 Results

.../reference/tsbuild/commandLine/multiFile/different-options-with-incremental-discrepancies.js

jakebailey

Some other stuff I noticed.

jakebailey · 2026-02-06T02:06:49Z

src/lib/es2025.intl.d.ts

+
+    type DurationFormatUnitSingular =
+        | "year"
+        | "quarter"


Is "quarter" real?

jakebailey · 2026-02-06T02:07:04Z

src/lib/es2025.intl.d.ts

+        locale?: UnicodeBCP47LocaleIdentifier;
+        numberingSystem?: DateTimeFormatOptions["numberingSystem"];
+        style?: DurationFormatStyle;
+        years?: Exclude<DurationFormatOption, "numeric" | "2-digit">;
+        yearsDisplay?: DurationFormatDisplayOption;
+        months?: Exclude<DurationFormatOption, "numeric" | "2-digit">;
+        monthsDisplay?: DurationFormatDisplayOption;
+        weeks?: Exclude<DurationFormatOption, "numeric" | "2-digit">;
+        weeksDisplay?: DurationFormatDisplayOption;
+        days?: Exclude<DurationFormatOption, "numeric" | "2-digit">;
+        daysDisplay?: DurationFormatDisplayOption;
+        hours?: DurationFormatOptions;
+        hoursDisplay?: DurationFormatDisplayOption;
+        minutes?: DurationFormatOptions;
+        minutesDisplay?: DurationFormatDisplayOption;
+        seconds?: DurationFormatOptions;
+        secondsDisplay?: DurationFormatDisplayOption;
+        milliseconds?: DurationFormatOptions;
+        millisecondsDisplay?: DurationFormatDisplayOption;
+        microseconds?: DurationFormatOptions;
+        microsecondsDisplay?: DurationFormatDisplayOption;
+        nanoseconds?: DurationFormatOptions;
+        nanosecondsDisplay?: DurationFormatDisplayOption;
+        fractionalDigits?: fractionalDigitsOption;


These options don't appear to be resolved; I think they should omit the ?.

jakebailey · 2026-02-06T02:16:04Z

I am actually quite confused why these intl changes are in ES2025. Doesn't https://github.com/tc39/proposal-intl-duration-format imply they are ES2024?

jakebailey · 2026-02-06T05:15:04Z

I think I'm just wrong; it's in https://tc39.es/ecma402/2025/ but not https://tc39.es/ecma402/2024/.

jakebailey · 2026-02-06T05:33:49Z

src/lib/es2025.intl.d.ts

+        | "day"
+        | "hour"
+        | "minute"
+        | "second";


I think this also needs milliseconds, microseconds, nanoseconds

jakebailey · 2026-02-06T05:35:00Z

src/lib/es2025.intl.d.ts

+        minutesDisplay?: DurationFormatDisplayOption;
+        seconds?: DurationFormatOptions;
+        secondsDisplay?: DurationFormatDisplayOption;
+        milliseconds?: DurationFormatOptions;


For milliseconds, microseconds, nanoseconds (not display), I think they need to be Exclude<DurationFormatOption, "2-digit"> (and below)

jakebailey · 2026-02-06T05:51:30Z

I realize I dumped a bunch of changes onto you; if you are too busy, I'm happy to just push the intl changes to the PR directly.

petamoriken · 2026-02-06T07:11:40Z

Instead of adding a new type as with other Intl type definitions, I wrote it inline within DurationFormatOptions. This might make the changes harder to review due to the volume. I apologize for the inconvenience.

src/lib/es2025.intl.d.ts

petamoriken · 2026-02-06T07:23:42Z

I realize I dumped a bunch of changes onto you; if you are too busy, I'm happy to just push the intl changes to the PR directly.

I have fixed most of it on my end. If the release of TypeScript 6.0 is imminent and you need the changes reflected immediately, please feel free to push directly to the PR 🙇

petamoriken · 2026-02-06T08:26:34Z

It seems that in es2023.intl.d.ts (Intl.NumberFormat) and es2022.intl.d.ts (Intl.Segmenter), types are defined inline within the options interfaces as much as possible, whereas in es2020.intl.d.ts (Intl.RelativeTimeFormat), types like RelativeTimeFormatUnit and RelativeTimeFormatUnitSingular are explicitly defined...

jakebailey · 2026-02-06T17:30:50Z

It seems that in es2023.intl.d.ts (Intl.NumberFormat) and es2022.intl.d.ts (Intl.Segmenter), types are defined inline within the options interfaces as much as possible, whereas in es2020.intl.d.ts (Intl.RelativeTimeFormat), types like RelativeTimeFormatUnit and RelativeTimeFormatUnitSingular are explicitly defined...

Yeah, I was thinking that we should do the middle ground, retaining:

DurationFormatLocaleMatcher
DurationFormatStyle
DurationFormatDisplayOption
DurationFormatUnit
DurationFormatUnitSingular

jakebailey · 2026-02-06T18:05:12Z

Ah, I just pushed to this, but didn't notice you were around to react. Well, I think it's in a good state now?

jakebailey · 2026-02-06T18:07:01Z

For some reason GitHub is not showing https://github.com/petamorike/TypeScript/commit/27bfccaac48540492a18f202227ed44c38b009a4 in this PR (and gh pr checkout did not pull it!), but it's there on your branch, and my commit comes after it and shows up...

jakebailey

Cross checked again, and looked at diffs that weren't simple replacements. All looks good.

I pushed to this last, so I can't approve, so I'll get someone to look.

DanielRosenwasser · 2026-02-06T19:00:19Z

tests/baselines/reference/callChainWithSuper(target=es2025).js

Why did this file get an output? Was its target incorrectly specified before?

The PR is too big to see that there are test cases at the very very bottom. If you view on github.dev or just clone, you can see it.

github-project-automation bot added this to PR Backlog Jan 24, 2026

github-project-automation bot moved this to Not started in PR Backlog Jan 24, 2026

typescript-bot added the For Backlog Bug PRs that fix a backlog bug label Jan 24, 2026

petamoriken changed the title ~~Introduce ES2025 target~~ Introduce ES2025 target & Add missing ScriptTargetFeatures Jan 24, 2026

petamoriken and others added 8 commits January 29, 2026 06:43

feat: Add ES2025 target

1f00226

fix: Add missing ScriptTargetFeatures

7c48e79

Add type for ES2025 RegExp.escape

f69d5ad

Co-authored-by: lionel-rowe <lionel.rowe@gmail.com>

Add type for ES2025 Intl.DurationFormat

bb08b4c

Co-authored-by: 김상두 <puki4416@gmail.com>

baseline

82d7c65

Tweak

f9ec910

typo

2003118

baseline

86c687a

petamoriken force-pushed the feat/es2025-target branch from 9d68792 to 86c687a Compare January 28, 2026 21:46

petamoriken added 4 commits January 29, 2026 06:52

remove "/en-US" from MDN URL

e86a117

Merge branch 'main' into feat/es2025-target

3ff5b2f

update ScriptTarget.LatestStandard to ES2025

57b8b0e

baseline

06350b4

petamoriken added 2 commits February 4, 2026 04:16

Merge branch 'main' into feat/es2025-target

4c718cd

Merge branch 'main' into feat/es2025-target

a684da6

petamoriken mentioned this pull request Feb 4, 2026

TypeScript 6.0 Iteration Plan #63085

Open

jakebailey reviewed Feb 4, 2026

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.../reference/tsbuild/commandLine/multiFile/different-options-with-incremental-discrepancies.js Outdated Show resolved Hide resolved

jakebailey reviewed Feb 6, 2026

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fix: getDefaultLibFileName

ff0e67c

fix Intl.DurationFormat types

29b9b1d

petamoriken commented Feb 6, 2026

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src/lib/es2025.intl.d.ts Show resolved Hide resolved

petamoriken commented Feb 6, 2026

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src/lib/es2025.intl.d.ts Show resolved Hide resolved

format

2e54cbc

fix CommandLineOptionOfCustomType

27bfcca

jakebailey mentioned this pull request Feb 6, 2026

"module": "nodenext" no longer infers "target": "esnext" in v7.0.0-dev.20260206.1 microsoft/typescript-go#2700

Closed

Middle ground

ac2a287

Typo

2fcf0f8

jakebailey approved these changes Feb 6, 2026

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DanielRosenwasser reviewed Feb 6, 2026

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DanielRosenwasser approved these changes Feb 6, 2026

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github-project-automation bot moved this from Not started to Needs merge in PR Backlog Feb 6, 2026

jakebailey added this pull request to the merge queue Feb 6, 2026

Merged via the queue into microsoft:main with commit ee09569 Feb 6, 2026
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github-project-automation bot moved this from Needs merge to Done in PR Backlog Feb 6, 2026

petamoriken deleted the feat/es2025-target branch February 7, 2026 02:36

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Related issues and (stalled) PRs

ES2025 RegExp.escape (es2025.regexp.d.ts)

ES2025 Intl.DurationFormat (es2025.intl.d.ts)

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petamoriken commented Jan 24, 2026 •

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ES2025 `RegExp.escape` (es2025.regexp.d.ts)

ES2025 `Intl.DurationFormat` (es2025.intl.d.ts)

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