TypeScript 4.4 Iteration Plan #44237

This document outlines our focused tasks for TypeScript 4.4. It minimally indicates intent to investigate tasks or contribute to an implementation. Nothing is set in stone, but we will strive to complete them in a reasonable timeframe.

Language and Compiler Features

• Stricter Optional/Missing vs. Undefined
• Generalized Index Signatures
• Strictness Flag for unknown in catch
• Investigate Incremental Warm-up Strategies
• --help Menu Updates
• Review the Project Setup Experience
• Investigate/Prototype Node.js 12 ESM Support
• lib.d.ts Updates

Editor Productivity

• Inline Hints
• Commit Characters in Server API
• Differentiate Definitions in References
• VS Code Welcome Screen Improvements
• Investigate High-Confidence "Did you Mean?" in JS
• Continue Enabling the Language Server Protocol (LSP)
• Investigate Debug Inline Values API

Performance

• Supporting Additional Trace Points
• Profiling/Tracing Mode Improvements
• Investigate Tooling for JIT Deoptimizations
• Use fs.realpathSync.native

Infrastructure

• Expand Perf Suite
• Fuzzer Improvements and Addressing Crashes
• Improving User Suite Reports
• master -> main
• Migrate to modules

Website

• Continue smoothing out first user experience
• Streamline website calls-to-action
• Gather UX feedback on playground
• Fix display issues on sample error spans

DefinitelyTyped

• Continue improving processes and performance