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TypeScript 5.4 Iteration Plan #56948
Description
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
NoInferIntrinsic - Isolated Declarations
- Investigate
--module preserveandrequire()in--moduleResolution bundler - Investigate and Review Regex Syntax Validation
- Checks for Never-Initialized Variables
- Champion
throwExpressions - 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.tsEmit - Communicate out Plan for 5.0 Deprecations in Anticipation of 5.5
Editor and Language Service
- Define Initial Sketch of LSP Support
- TSServer File-Watching Events
- Organize Imports Respecting
typeImports - Investigate AI-powered Refactorings
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
Activity
DanielRosenwasser commentedon Jan 4, 2024
You can see the previous iteration plan for 5.3 here.
JoshuaKGoldberg commentedon Jan 4, 2024
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 commentedon Jan 7, 2024
It's not clear to me what this means. I thought TSC already was LSP-compliant?
jakebailey commentedon Jan 7, 2024
tsserver uses the tsserver protocol, which predates LSP. It does not (yet) implement LSP.
guillaumebrunerie commentedon Jan 7, 2024
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 usedtsserverdirectly 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 commentedon Jan 7, 2024
The latter, though there are of course other benefits.
jfet97 commentedon Jan 11, 2024
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 Mateusz Burzyński (@Andarist) happy.
DanielRosenwasser commentedon Jan 22, 2024
TypeScript Bot (@typescript-bot) create release-5.4
typescript-bot commentedon Jan 22, 2024
Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to create the
release-5.4branch for you. Here's the link to my best guess at the log.DanielRosenwasser commentedon Jan 22, 2024
Jake says he fixed the build.
TypeScript Bot (@typescript-bot) create release-5.4
typescript-bot commentedon Jan 22, 2024
Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to create the
release-5.4branch for you. Here's the link to my best guess at the log.dimitur2204 commentedon Jan 24, 2024
Finally!
DanielRosenwasser commentedon Jan 25, 2024
TypeScript Bot (@typescript-bot) sync release-5.4
10 remaining items
ghiscoding commentedon Feb 20, 2024
Daniel Rosenwasser (@DanielRosenwasser) is the v5.4 RC release still scheduled for today? I don't see it yet on NPM. Thanks
DanielRosenwasser commentedon Feb 20, 2024
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 commentedon Feb 27, 2024
The previous comments mention an issue with the build pipeline around the RC release, but I now see a
5.4.1-rcrelease on npm. Would it be correct to assume that the 5.4 RC is out now?jakebailey commentedon Feb 27, 2024
Yes: https://devblogs.microsoft.com/typescript/announcing-typescript-5-4-rc/
Add `typescript@rc` to test for `[email protected]` (#500)
DanielRosenwasser commentedon Mar 4, 2024
TypeScript Bot (@typescript-bot) bump release-5.4
typescript-bot commentedon Mar 4, 2024
Starting jobs; this comment will be updated as builds start and complete.
bump release-5.4typescript-bot commentedon Mar 4, 2024
Hey, Daniel Rosenwasser (@DanielRosenwasser)! I've set the version of release-5.4 to 5.4.2 for you.
RyanCavanaugh commentedon Mar 6, 2024
Anonymous4078 you ok?
DanielRosenwasser commentedon Mar 15, 2024
TypeScript Bot (@typescript-bot) bump release-5.4
typescript-bot commentedon Mar 15, 2024
Starting jobs; this comment will be updated as builds start and complete.
bump release-5.4typescript-bot commentedon Mar 15, 2024
Hey, Daniel Rosenwasser (@DanielRosenwasser)! I've set the version of release-5.4 to 5.4.3 for you.
DanielRosenwasser commentedon Mar 20, 2024
5.4.3 is out! https://github.com/microsoft/TypeScript/releases/tag/v5.4.3