TypeScript 6.0 RC has been released as the final version of the original compiler engine before a full rewrite in Go ships as TypeScript 7.0. Key additions include support for the Temporal API (replacing the Date object), types for Map.getOrInsert and RegExp.escape, and merging dom.iterable into the core dom library. Major breaking changes include removal of ES5 output, deprecation of AMD/UMD/SystemJS module formats, strict mode now defaulting to true, deprecation of --baseUrl, and the types config field now defaulting to an empty array instead of auto-loading all @types packages. The last change can cut build times by 20–50% but will cause 'Cannot find name' errors for unprepared projects. Teams are advised to upgrade now, address deprecation warnings, and explicitly declare their types array to ease the eventual transition to TypeScript 7.0.
Table of contents
What’s actually newWhat’s going awayThe change most likely to break thingsThe bottom lineSort: