TypeScript 5.4 Iteration Plan #56948

DanielRosenwasser · 2024-01-04T19:37:50Z

This document outlines our focused tasks for TypeScript 5.4. It minimally indicates intent to investigate tasks or contribute to an implementation. Nothing is set in stone, but we will strive to complete these tasks in a reasonable timeframe.

Date	Event
2023-11-20	TypeScript 5.3 Release
2024-01-19	Create 5.4 Beta (5.4.0) Build for Testing
2024-01-23	TypeScript 5.4 Beta Release
2024-02-16	Create 5.4 RC (5.4.1) Build for Testing
2024-02-20	TypeScript 5.4 RC Release
2024-03-01	Create 5.4 Final (5.4.2) Build for Testing
2024-03-05	TypeScript 5.4 Final Release 🚀

gantt
    dateFormat  YYYY-MM-DD
    TypeScript 5.3 Stabilization Period : 2023-11-03, 2023-11-20
    TypeScript 5.4 Beta Development : 2023-11-03, 2024-01-19
    TypeScript 5.4 RC Development : 2024-01-20, 2024-02-16
    TypeScript 5.4 Stabilization Period : 2024-02-16, 2024-03-05
todayMarker stroke-width:5px,stroke:#0f0,opacity:0.5

Compiler and Language

Type Narrowing for Variables in Closures Occurring After Last Assignments
The NoInfer Intrinsic
Isolated Declarations
Investigate --module preserveand require() in --moduleResolution bundler
Investigate and Review Regex Syntax Validation
Checks for Never-Initialized Variables
Champion throw Expressions
Investigate Function Implementations Returning Indexed Access and Conditional Types
Make isTypeAssignableTo public on TypeChecker #56448
Alleviating Pain-Points around dual-ESM/CJS-published Packages
Investigate Syntactic Variance Measurement
Symbol Visibility Walk Optimizations for .d.ts Emit
Communicate out Plan for 5.0 Deprecations in Anticipation of 5.5

Editor and Language Service

Performance

Investigate Running With V8 Snapshots
Parallelization Experimentation

Website and Docs

Infrastructure

Expand Performance Suite
Move DefinitelyTyped to GitHub Actions
DefinitelyTyped Monorepo Improvements
arethetypeswrong validation in DefinitelyTyped

The text was updated successfully, but these errors were encountered:

DanielRosenwasser · 2024-01-04T19:38:57Z

You can see the previous iteration plan for 5.3 here.

JoshuaKGoldberg · 2024-01-04T21:59:27Z

Make isTypeAssignableTo public on TypeChecker #56448

This is one of the most exciting release points for us in typescript-eslint in a long time. Very high benefit here. Very much hoping there's no last-minute issue discovered. Thank you! 🙌

zaguiini · 2024-01-07T00:45:21Z

Define Initial Sketch of LSP Support

It's not clear to me what this means. I thought TSC already was LSP-compliant?

jakebailey · 2024-01-07T01:22:01Z

tsserver uses the tsserver protocol, which predates LSP. It does not (yet) implement LSP.

guillaumebrunerie · 2024-01-07T09:37:49Z

tsserver uses the tsserver protocol, which predates LSP. It does not (yet) implement LSP.

I've been using https://github.com/typescript-language-server/typescript-language-server#readme (a LSP implementation for TypeScript wrapping tsserver) with Emacs for quite some time and it works perfectly well, but I've never used tsserver directly so I'm not sure if there are any features that I'm missing.

Would a native implementation of LSP have any user-visible consequences, compared to using a wrapper like this one? Or is it mostly about supporting LSP officially and removing the need for a third-party wrapper?

jakebailey · 2024-01-07T18:56:33Z

Would a native implementation of LSP have any user-visible consequences, compared to using a wrapper like this one? Or is it mostly about supporting LSP officially and removing the need for a third-party wrapper?

The latter, though there are of course other benefits.

jfet97 · 2024-01-11T09:03:44Z

I'll share a link to Reverse mapped types with intersection constraint as well 😛, both for its enabling of type inference and Excess Property Checking together, and for doing some advertising for reverse mapped types, making @Andarist happy.

DanielRosenwasser · 2024-01-22T00:48:04Z

@typescript-bot create release-5.4

typescript-bot · 2024-01-22T00:48:10Z

Heya @DanielRosenwasser, I've started to create the release-5.4 branch for you. Here's the link to my best guess at the log.

DanielRosenwasser · 2024-01-22T05:27:31Z

Jake says he fixed the build.

@typescript-bot create release-5.4

typescript-bot · 2024-01-22T05:27:37Z

Heya @DanielRosenwasser, I've started to create the release-5.4 branch for you. Here's the link to my best guess at the log.

dimitur2204 · 2024-01-24T19:41:58Z

Define Initial Sketch of LSP Support

Finally!

DanielRosenwasser · 2024-01-25T00:36:56Z

@typescript-bot sync release-5.4

typescript-bot · 2024-01-25T00:37:03Z

Heya @DanielRosenwasser, I've started to sync release-5.4 with main for you. Here's the link to my best guess at the log.

DanielRosenwasser · 2024-01-26T18:10:36Z

Just as a heads up, we will probably go out with the 5.4 beta next Monday, since we're having some issues with the NuGet side of the build pipeline.

DanielRosenwasser · 2024-01-28T10:22:42Z

@typescript-bot sync release-5.4

typescript-bot · 2024-01-28T10:22:49Z

Heya @DanielRosenwasser, I've started to sync release-5.4 with main for you. Here's the link to my best guess at the log.

linbudu599 · 2024-01-29T02:30:02Z

Just as a heads up, we will probably go out with the 5.4 beta next Monday, since we're having some issues with the NuGet side of the build pipeline.

Also when are we probably going to see the devblog? Just be really excited to see it.

DanielRosenwasser · 2024-01-29T20:04:37Z

5.4 Beta is now published:

DanielRosenwasser · 2024-02-19T05:57:03Z

@typescript-bot sync release-5.4

typescript-bot · 2024-02-19T05:57:10Z

Heya @DanielRosenwasser, I've started to sync release-5.4 with main for you. Here's the link to my best guess at the log.

DanielRosenwasser · 2024-02-19T06:01:25Z

@typescript-bot bump release-5.4

typescript-bot · 2024-02-19T06:01:30Z

Heya @DanielRosenwasser, I've started to update the version number on release-5.4 to 5.4.1-rc for you. Here's the link to my best guess at the log.

ghiscoding · 2024-02-20T20:13:42Z

@DanielRosenwasser is the v5.4 RC release still scheduled for today? I don't see it yet on NPM. Thanks

DanielRosenwasser · 2024-02-20T23:02:20Z

No, unfortunately another issue with our build pipeline occurred. Otherwise, you can use the most recent nightly version of TypeScript to capture a (mostly?) identical version.

crisbeto · 2024-02-27T17:53:06Z

The previous comments mention an issue with the build pipeline around the RC release, but I now see a 5.4.1-rc release on npm. Would it be correct to assume that the 5.4 RC is out now?

jakebailey · 2024-02-27T17:56:41Z

Yes: https://devblogs.microsoft.com/typescript/announcing-typescript-5-4-rc/

## Summary  Adds `typescript@rc` (currently `typescript@5.4.0`). This is used to test the 5.4 release candidate to resolve any issues before it ships. When it does, we'll move this PR to target `typescript@5.4.0` and merge, including a changeset if any changes needed to be made. We should ship this change once the final build is submitted at the beginning of March. See microsoft/TypeScript#56948 ## Checklist    - [ ] ~Added a [docs PR](https://github.com/inngest/website) that references this PR~ N/A - [x] Added unit/integration tests - [x] Added changesets if applicable ## Related - microsoft/TypeScript#56948

DanielRosenwasser · 2024-03-04T06:46:15Z

@typescript-bot bump release-5.4

typescript-bot · 2024-03-04T06:46:17Z

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

Command	Status	Results
`bump release-5.4`	✅ Started	✅ Results

typescript-bot · 2024-03-04T06:55:32Z

Hey, @DanielRosenwasser! I've set the version of release-5.4 to 5.4.2 for you.

RyanCavanaugh · 2024-03-06T22:38:29Z

@Anonymous4078 you ok?

DanielRosenwasser · 2024-03-15T19:31:19Z

@typescript-bot bump release-5.4

typescript-bot · 2024-03-15T19:31:21Z

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

Command	Status	Results
`bump release-5.4`	✅ Started	✅ Results

typescript-bot · 2024-03-15T19:40:28Z

Hey, @DanielRosenwasser! I've set the version of release-5.4 to 5.4.3 for you.

DanielRosenwasser · 2024-03-20T19:36:15Z

5.4.3 is out! https://github.com/microsoft/TypeScript/releases/tag/v5.4.3

DanielRosenwasser added the Planning Iteration plans and roadmapping label Jan 4, 2024

DanielRosenwasser pinned this issue Jan 4, 2024

DanielRosenwasser mentioned this issue Jan 4, 2024

TypeScript 5.3 Iteration Plan #55486

Open

MartinJohns mentioned this issue Jan 4, 2024

Iteration Plan for 5.4 release? #56945

Closed

oliviertassinari mentioned this issue Jan 23, 2024

[typescript] Replace Array API with ReadonlyArray mui/material-ui#40750

Open

osyrisrblx mentioned this issue Feb 13, 2024

Upgrade TypeScript roblox-ts/roblox-ts#2610

Closed

DanielRosenwasser mentioned this issue Feb 22, 2024

TypeScript 5.5 Iteration Plan #57475

Open

jpwilliams mentioned this issue Feb 28, 2024

Add typescript@rc to test for typescript@5.4 inngest/inngest-js#500

Merged

3 tasks

TypeScript 5.4 Iteration Plan #56948

TypeScript 5.4 Iteration Plan #56948

Comments

DanielRosenwasser commented Jan 4, 2024

Compiler and Language

Editor and Language Service

Performance

Website and Docs

Infrastructure

DanielRosenwasser commented Jan 4, 2024

JoshuaKGoldberg commented Jan 4, 2024 • edited

zaguiini commented Jan 7, 2024

jakebailey commented Jan 7, 2024

guillaumebrunerie commented Jan 7, 2024

jakebailey commented Jan 7, 2024

jfet97 commented Jan 11, 2024

DanielRosenwasser commented Jan 22, 2024

typescript-bot commented Jan 22, 2024

DanielRosenwasser commented Jan 22, 2024

typescript-bot commented Jan 22, 2024

dimitur2204 commented Jan 24, 2024 • edited

DanielRosenwasser commented Jan 25, 2024

typescript-bot commented Jan 25, 2024

DanielRosenwasser commented Jan 26, 2024

DanielRosenwasser commented Jan 28, 2024

typescript-bot commented Jan 28, 2024

linbudu599 commented Jan 29, 2024

DanielRosenwasser commented Jan 29, 2024

DanielRosenwasser commented Feb 19, 2024

typescript-bot commented Feb 19, 2024

DanielRosenwasser commented Feb 19, 2024

typescript-bot commented Feb 19, 2024

ghiscoding commented Feb 20, 2024

DanielRosenwasser commented Feb 20, 2024

crisbeto commented Feb 27, 2024

jakebailey commented Feb 27, 2024

DanielRosenwasser commented Mar 4, 2024

typescript-bot commented Mar 4, 2024 • edited

typescript-bot commented Mar 4, 2024

RyanCavanaugh commented Mar 6, 2024

DanielRosenwasser commented Mar 15, 2024

typescript-bot commented Mar 15, 2024 • edited

typescript-bot commented Mar 15, 2024

DanielRosenwasser commented Mar 20, 2024 • edited

JoshuaKGoldberg commented Jan 4, 2024 •

edited

dimitur2204 commented Jan 24, 2024 •

edited

typescript-bot commented Mar 4, 2024 •

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typescript-bot commented Mar 15, 2024 •

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DanielRosenwasser commented Mar 20, 2024 •

edited