TypeScript native compiler adds experimental WebAssembly support
Published: 2026-10-29
Microsoft merged experimental wasip1/wasm support for the native TypeScript compiler on October 29, 2026. The change makes the compiler usable in WASI hosts and introduces a browser-capable JavaScript API transport.
What changed
- The same
tsc.wasmcan run as a WASI command for the CLI or language server, or as a reactor for synchronous and asynchronous JavaScript API calls. - A new artifact package,
@typescript/typescript-wasip1-wasm, contains the WebAssembly compiler and library files. Thetypescript/wasmhost providesinstantiateWasmandinstantiateWasmSync; both packages must use the same exact version. - The VS Code for Web extension gains an entry point that runs
tsc.wasm --lsp. The change includes Node.js API tests and Chromium browser smoke tests.
Availability
This is an experimental merged change, not an announcement of a stable WebAssembly release. The binary, package layout, and typescript/wasm host may change without notice.