Why TypeScript 7 Promises Up to 10× Faster Compilation and a Go‑Powered Future

Microsoft's TypeScript team revealed that the upcoming TypeScript 7 toolchain, codenamed Corsa, is in its final stage. It provides near‑full compatibility and stability for real‑world projects and delivers up to ten‑fold faster compilation speeds on large codebases.

They also announced that TypeScript 6.0 will be the last version implemented in JavaScript (Strada); future development will focus on a compiler and language service written in Go.

A new native preview extension for VS Code introduces a TypeScript language service supporting autocomplete, go‑to‑definition, rename, signature help, and other core features for both TypeScript and JavaScript projects. The service was rewritten using a shared‑memory parallel architecture, reducing memory consumption, load time, and improving stability.

Performance is the primary focus of the native implementation. Benchmarks comparing the existing JavaScript compiler (tsc) with the Go implementation (tsgo) show that tsgo is roughly 7–10× faster even without the --incremental flag, dramatically shortening full rebuild times.

Current limitations include: TypeScript 7's JavaScript output can only down‑level to ES2021, decorators are not yet supported, the old compiler API is unavailable, and tooling must still rely on the TS 6.0 API.

The JSDoc type‑checking system has been redesigned, removing loosely used patterns such as @enum and @constructor, and no longer treating Object as any or String as string automatically. Projects that rely heavily on JSDoc‑only typing may see new errors and need to adjust comments or gradually adopt TypeScript syntax.