TypeScript 7 Is 10x Faster. Here's What Changed Inside

TypeScript 7 type-checks the VS Code codebase in 10 seconds. It used to take two minutes. Same type system, no new syntax. Here's where the speed actually came from. The compiler is now in Go, but they didn't rewrite it. They ported it function by function so the old test suite still applies. I go through why that beat a rewrite, why they picked Go over Rust, how 4 parallel type-checkers split up your files, what the --checkers, --builders and --singleThreaded flags do, why the editor went from 17.5s to 1.3s to show an error, and what breaks in your tsconfig when you upgrade. At the end: what the 7.1 beta's new API means for typescript-eslint, Vue and Svelte users. Chapters 0:00 10x faster, same compiler 1:02 Port, not rewrite 2:28 Why Go, not Rust 4:09 Where the speed comes from 6:34 The editor gets LSP 7:27 What breaks when you upgrade 9:12 7.1 and my take Links to resources: Announcing TypeScript 7.0: https://devblogs.microsoft.com/typesc... Announcing TypeScript 7.1 Beta: https://devblogs.microsoft.com/typesc... typescript-eslint: https://typescript-eslint.io/ #typescript #javascript #webdevelopment