Announcing TypeScript 4.5 RC
Today we’re excited to announce our Release Candidate (RC) of TypeScript 4.5! Between now and the stable release of TypeScript 4.5, we expect no further changes apart from critical bug fixes.
What’s New Since the Beta?
Since our beta release post, 4.5 has gone through a few changes.
The biggest change we’ve made since the beta is that ECMAScript module support for Node.js 12 has been deferred to a future release, and is now only available as an experimental flag in nightly releases. This was not an easy decision, but our team had a combination of concerns around ecosystem readiness and general guidance for how/when to use the feature. We felt it would be better to smooth out the user experience instead of releasing something that would ultimately be too frustrating for most people. In the meantime though, you can still use the new support for --module nodenext and --moduleResolution nodenext as experimental features in nightly builds of TypeScript. If you try to use these settings in TypeScript 4.5 RC or stable, you’ll receive an error message directing you to use a nightly build instead.
From the language editing side, we’ve introduced more snippet completions – specifically, for method implementation and overrides.
We’ve also addressed a performance regression in --build mode due to excessive realpath calls for package.json files. This change was made for TypeScript 4.5, but was also back-ported to TypeScript 4.4.4. If this regression blocked you from trying TypeScript 4.4, you should see comparable or better speed in --build mode compared to past versions.
Microsoft has released the release candidate for TypeScript 4.5.
