TypeScript 7.0 Beta is out, and the compiler has been rewritten from Node.js to Go. Same type system, same syntax, same compiler options, just a completely different execution model: no V8 JIT warmup, no GC pauses, and true parallel type-checking across CPU cores.
The real-world numbers are hard to ignore:
| Project | TS 6 (tsc) | TS 7 (tsgo) | Speedup |
|---|---|---|---|
| VS Code (1.5M lines) | 78s | 7.5s | 10.4x |
| Sentry (large monorepo) | 133s | 16s | 8.3x |
| Medium Node backend (~100k lines) | 12s | 2.1s | 5.7x |
The bigger the codebase, the bigger the win, since parallelism gains compound at scale.
The new binary is called tsgo. The old tsc still works through a compatibility shim, but it won't get future performance work, everything new goes into tsgo from here.
Before upgrading, there are 4 breaking changes worth knowing:
- Import assertions (
assert) are removed in favor of import attributes (with) - JSDoc
@enumis removed for.jsfiles - Prototype reassignment loses its special-cased type inference
- Legacy
thisaliasing patterns may type slightly differently and often need an arrow-function refactor
None of these affect most modern codebases on current syntax, but worth checking before you commit.
In the full guide, I cover the install steps for the native preview package, a side-by-side tsc vs tsgo comparison workflow, a CI/CD setup that runs both during migration without blocking builds, removed tsconfig options, monorepo behavior with project references, and a decision table for whether you should upgrade now or wait for stable.
👉 Read the full migration guide: https://devencyclopedia.com/blog/typescript-7-migration-guide
Top comments (0)