TypeScript 4.5 also introduces a way to override a specific built-in lib in a manner similar to how works. This solves some problems around inference with Promise.all that would have failed in earlier releases, Microsoft said. What TypeScript 4.5 RC does add is a new utility type called the Awaited type, which is intended to be helpful for modelling existing APIs like await in async functions, as well including JavaScript built-ins like Promise.all, Promise.race. Microsoft said it felt that the current support needed more “bake time” and it was better to smooth out the user experience instead of releasing something that would ultimately be too frustrating for many users. TypeScript 4.5 was expected to feature ECMAScript module support for Node.js 12, but this has now been deferred to a future release, although it will still be available as an experimental feature in nightly releases of the platform. This release puts the ECMAScript module support for Node.js on hold, but Microsoft otherwise expects no further changes between this and the stable release of TypeScript 4.5 apart from critical bug fixes.

Microsoft has made available a Release Candidate (RC) for TypeScript 4.5, its programming language that builds on the capabilities of JavaScript.

Ecmascript 2021