TypeScript 5.6 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 5.6. 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
2024-06-18	TypeScript 5.5 Release
2024-07-19	Create 5.6 Beta (5.6.0) Build for Testing
2024-07-23	TypeScript 5.6 Beta Release
2024-08-16	Create 5.6 RC (5.6.1) Build for Testing
2024-08-20	TypeScript 5.6 RC Release
2024-08-30	Create 5.6 Final (5.6.2) Build for Testing
2024-09-03	TypeScript 5.6 Final Release 🚀

gantt
    dateFormat  YYYY-MM-DD
    TypeScript 5.5 Stabilization Period : 2024-06-10, 2024-06-18
    TypeScript 5.6 Beta Development : 2024-06-10, 2024-07-20
    TypeScript 5.6 RC Development : 2024-07-20, 2024-08-16
    TypeScript 5.6 Stabilization Period : 2024-08-16, 2024-09-03
todayMarker stroke-width:5px,stroke:#0f0,opacity:0.5

Loading

Compiler and Language

• Investigate Strict Callback Analysis
• Stricter TReturn and TNext Types for next() on Iterators
• Checks for Never-Initialized Variables
• ECMAScript Arbitrary Module Identifiers
• Consult type in node_modules/**/package.json in More Module Modes
• Spelling Suggestions for Named Capture Groups
• Investigate skipCheck/noCheck in API and Batch-Mode Compilation
• Build All Projects Under --build Irrespective of Errors
• Investigate Non-Null Assertions in JSDoc
• lib.d.ts Updates

Editor and Language Service

• Investigate Expandable Quick Info/Hover Verbosity
• Region-Prioritized Error Checking
• Investigate Simpler Quick Fix API
• Investigate LSP Support
• Auto-Import on Paste
• Provide Deprecated Diagnostics on Namespaces Declared with module Keyword

Performance

• Investigate and Experiment with Full Monomorphization
• Investigate Wildcard Matching Performance
• Optimize Path Mapping Lookups
• Investigate Deferring TransformFlags Calculation

Website and Docs

• Revisit/Review Handbook and Experiences
• Simplify and Refactor Website for Faster Builds

Infrastructure

• Investigate Provenance or Build Signing
• Experiment with Reduced Repros on Weekly New Error Runs
• Adopt --isolatedDeclarations and Parallelize TypeScript's Build

[MunMunMiao]

I hope you can consider #26242 and #59126. We really hope to be able to use optional generics.

[ghiscoding]

Could this next plan be pinned instead of previous 5.5 which is now closed, it was hard to find. Thanks