This document outlines our focused tasks for TypeScript 4.1. Nothing is set in stone, but we will strive to complete them in a reasonable timeframe. Date | Event ---------------|------------------------- August 20th | TypeScript 4.0 Release September 11th | Create 4.1 Beta (4.1.0) Build for Testing September 15th | **TypeScript 4.1 Beta Release** October 30th | Create 4.1 RC (4.1.1) Build for Testing November 3rd | **TypeScript 4.1 RC Release** November 13th | Create 4.1 Final (4.1.2) Build for Testing November 17th | **TypeScript 4.1 Final Release** 🚀 ## Language Features * [Recursive Conditional Types](https://github.com/microsoft/TypeScript/pull/40002) * Investigate Pedantic Flags * [`undefined` in index signatures](https://github.com/microsoft/TypeScript/issues/13778) * [`--noImplicitOverride`](https://github.com/microsoft/TypeScript/issues/2000) * Investigate Preventing [Global Conflicts](https://github.com/microsoft/TypeScript/issues/32273) with Strict Environment Configuration * [Investigate Key Augmentations in Mapped Types](https://github.com/microsoft/TypeScript/issues/12754) * [Investigate ESM Interop](https://nodejs.org/api/esm.html#esm_enabling) * [`export * as default`](https://github.com/microsoft/TypeScript/issues/39769) * [Investigate WASM imports](https://github.com/microsoft/TypeScript/pull/39784) * [JSX Factory Updates](https://github.com/microsoft/TypeScript/issues/34547) * [Investigate `///` Comments](https://github.com/microsoft/TypeScript/pull/39930) ## Editor Productivity * [New Semantic Highlighting API](https://github.com/microsoft/TypeScript/issues/38435) * [Enable running TSServer in a worker thread](https://github.com/microsoft/TypeScript/issues/39707) * [Hierarchal Refactoring Triggers](https://github.com/microsoft/TypeScript/issues/35096) * [Improve Refactoring Discoverability](https://github.com/microsoft/TypeScript/issues/37895) * [JS Inference Improvements](https://github.com/microsoft/TypeScript/issues/40025) * [Investigate Support for `@see` and `@link` Tags](https://github.com/microsoft/TypeScript/issues/35524) * [ATA Updates](https://github.com/microsoft/TypeScript/issues/40123) ## Performance * Anticipated bug fixes and [UX improvements](https://github.com/microsoft/TypeScript/issues/39035) for partial semantic mode * [`tsc` Profiling Output Support](https://github.com/microsoft/TypeScript/pull/40063) * [Investigate Slowdowns in Popular Libraries](https://github.com/microsoft/TypeScript/issues/34801) ## Infrastructure * Improve Workflow for External Code Tests * Breaking Change Detection Scripts