tsc-rs 0.7.0 runs its checker on wasm32 with less memory

The 8 October account covered tsc-rs 0.1.0, Theo Browne’s early Rust port of Microsoft’s Go TypeScript compiler. The repository is pingdotgg/ts-rust. The npm package is tsc-rs. Since then the package has moved from 0.1.0 to 0.7.0. On 16 October 2026 the npm registry latest tag was 0.7.0, published at 10:04 UTC on 14 October. The GitHub release was published at 10:02 UTC the same day. The registry license field on 0.7.0 reads MIT AND Apache-2.0.

What each release note highlights

The times below are GitHub’s published_at on the releases list.

0.2.0, 9 October 2026 at 21:50 UTC, includes a Linux arm64 build and a change titled “ship PGO builds of the tsc.” The README at the v0.7.0 tag says npm packages from 0.2.0 on are built in CI with profile-guided optimization and without BOLT, and that 0.1.0 had neither.

0.3.0, 11 October at 08:42 UTC, adds Windows x64, Intel macOS, and Windows arm64 binaries. The 0.7.0 registry record lists optional packages for Linux, Windows, and macOS, each on x64 and arm64.

0.6.0, 13 October at 06:56 UTC, says long edit sessions grow 3.1 to 4.6 MiB per 1,000 edits, down from about 20 MiB in 0.5.0, and that after 10,000 edits the language server uses less memory than tsc on TanStack Query core and Hono. The same note says 184,749 ported Go tests pass, and that none were lost since 0.5.0. The v0.7.0 README says 184,773 ported Go tests pass. The two figures differ by 24. They are left as each source wrote them.

0.7.0 lists two changes: README benchmark numbers for 0.6.0, including --fast, and “fix(wasm): run the checker on wasm32 with less memory.” That second line is the release’s description of the wasm32 work. It says the checker runs on wasm32, and that it uses less memory. It does not describe a new sandbox product.

The README’s six-app table is labeled tsc-rs 0.6.0, measured 13 October 2026 on 16-vCPU runners, a release build with profile-guided optimization and without BOLT. On that table the geometric mean versus TypeScript 7 is 2.10 times in the default mode and 2.90 times with --fast. Versus TypeScript 6 the same table lists 15.3 times and 21.2 times. Those multiples belong to that README run, on 0.6.0.

What The Register reported

Joab Jackson’s story in The Register, 15 October 2026 at 19:52 UTC, says Browne claims the port runs twice as fast as Microsoft’s Go TypeScript rewrite and 12.5 times as fast as TypeScript 6. The story calls the project TS_Rust. The repository name is pingdotgg/ts-rust and the package name is tsc-rs. The article text does not name version 0.7.0. “Twice” and “12.5 times” are Browne’s claims as The Register reports them. They are separate numbers from the 0.6.0 table above.

The same story reports Browne’s argument that a Rust checker could let some agent workloads run inside V8, compiled to WebAssembly, instead of a virtual machine or a container. That framing is his argument in the article. The 0.7.0 note only says the checker runs on wasm32 with less memory.

The registry’s next tag still pointed at 0.2.0 on 16 October. npm install -D tsc-rs follows latest, which was 0.7.0. The 0.1.0 write-up still holds the early warnings, including Browne’s line that he had not read the code.