This document outlines our focused tasks for TypeScript 4.8. 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.

Language and Compiler Features

• ECMAScript Decorators
• Improved Inference for infer Types in Template String Types
• Investigate Contextually Typed And Compatible Operator
• Continue Investing in Type Annotations Proposal
• Investigate --isolatedDeclaration Emit Mode
• Improve Conformance for Arrow Functions in Conditional Expressions
• Investigate Narrowing Generics By Truthiness
• Investigate --watch Issues on Checkouts
• lib.d.ts Updates

Editor Productivity

• Prototype Virtual File System Support in TSServer
• Investigate Cancellation in Browser Contexts
• Prototype Automatic Type Acquisition in Web Contexts
• Provide Walkthroughs in Visual Studio Code Welcome View
• Easy Run/Debug for Loose TypeScript Files
• Investigate TS Server Plugins on the Web

Performance

• Investigate Tooling for JIT Deoptimizations
• Investigate Outstanding Performance Issues
• Enrich TS Server Tracepoint

Infrastructure

• Determining Module Migration and Shipping Strategy
• Fuzzer Improvements and Addressing Crashes
• TSServer Performance Testing Infrastructure
• Expand Perf Suite

Website

• Accessibility Improvements
• Investigate Playground as a VS Code Extension