TypeScript 5.7 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 5.7. 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
2024-09-09	TypeScript 5.6 Release
2024-09-27	Create 5.7 Beta (5.7.0) Build for Testing
2024-10-01	TypeScript 5.7 Beta Release
2024-11-08	Create 5.7 RC (5.7.1) Build for Testing
2024-11-12	TypeScript 5.7 RC Release
2024-11-18	Create 5.7 Final (5.7.2) Build for Testing
2024-11-21	TypeScript 5.7 Final Release 🚀

Compiler and Language

• Control Flow Analysis for Lambdas Passed to immediate Parameters
• Enforce Readonly Checks on Object Members
• Checks for Never-Initialized Variables
• Disallow Parameter Property References from Class Fields
• Investigate Relating Values to Conditional Return Types
• Investigate Relative Import Extension Rewrites
• Investigate /** @typeArguments/specialize */
• Investigate Support for Sourcemap v4
• lib.d.ts Updates

Editor and Language Service

• Investigate Expandable Quick Info/Hover Verbosity
• Consult Root Files Before Opening composite Projects
• Ancestor Configuration File Searching
• Completions for package.json Subpath imports
• Improved Rename for Shorthand Properties/Destructuring
• Support "Prepare Paste Edits" Command
• Ship Import-on-Paste in Stable VS Code
• Improved Detection of node: for Auto-Import Paths
• Investigate File Drop Support in Editor
• Investigate Improved Move to File Naming
• Investigate LSP Support

Performance

• Path Mapping Optimizations
• Investigate Enabling V8 Compile Caching in Node.js
• Investigate and Experiment with Full Monomorphization

Website and Docs

• Simplify and Refactor Website for Faster Builds
• Handbook Review
• Experiment with Example-Driven Learning Paths

Infrastructure

• Experiment with Reduced Repros on Weekly New Error Runs
• Consider --isolatedDeclarations
• Use ProjectService when Running TS ESLint

[petamoriken]

I hope ES2024 target (#58573) will be added. It's blocked by #59417.

[trevorade]

Are the dates for 5.7 still accurate or do they need an update?

I looked at the linked Compiler and Language issues / PRs and most of them are not committed. The beta is scheduled 6 days from now. I'm unclear on what the typical timing is between commits and the Beta (or if all the intended commits are actually in the Beta)

[pociej]

Is es2024 target support planned to be included?

[HolgerJeromin]

@pociej
#58573 was merged a few days ago, so yes this will be included.

[DanielRosenwasser]

@typescript-bot create release-5.7

[typescript-bot]

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

Command	Status	Results
create release-5.7	✅ Started	❌ Results

[typescript-bot]

Hey, @DanielRosenwasser! I was unable to create the new release branch.

Check the logs at: https://github.com/microsoft/TypeScript/actions/runs/11115678209

[DanielRosenwasser]

@typescript-bot create release-5.7

[typescript-bot]

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

Command	Status	Results
create release-5.7	✅ Started	❌ Results

[typescript-bot]

Hey, @DanielRosenwasser! I was unable to create the new release branch.

Check the logs at: https://github.com/microsoft/TypeScript/actions/runs/11116217953

[typescript-bot]

Hey, @DanielRosenwasser! I was unable to create the new release branch.

Check the logs at: https://github.com/microsoft/TypeScript/actions/runs/11116217953

[DanielRosenwasser]

@typescript-bot create release-5.7

[typescript-bot]

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

Command	Status	Results
create release-5.7	✅ Started	✅ Results

[typescript-bot]

Hey, @DanielRosenwasser! I've created release-5.7 with version 5.7.0-beta for you.

[DanielRosenwasser]

Hey all, to be transparent, we have fallen behind a bit on the plans. The beta will be delayed by up to a week, though that doesn't mean we'll be bringing in everything that's still outstanding in the compiler + language. Thanks for the patience everyone!