Tabs / Steps / FileTree parse HTML at render time via Sätteri, breaking non-Node SSR runtimes (Cloudflare workerd) #4194

What version of starlight are you using?

0.42.0

What version of astro are you using?

7.3.2

What package manager are you using?

pnpm

What operating system are you using?

Mac

What browser are you using?

Chrome

Describe the Bug

Tabs, Steps and FileTree call htmlToHast() from satteri at render time (dist/user-components/{tabs,steps,file-tree}-processor.js). Sätteri ships only a native .node binding and a WASI binding, and neither can run in Cloudflare's workerd runtime:

the native .node addon cannot be loaded at all;
the WASI binding (@bruits/satteri-wasm32-wasi) touches node:wasi at module evaluation, and workerd's stub throws The WASI method is not implemented.

So any page containing <Tabs> fails with the Cloudflare adapter, whose default prerenderEnvironment is 'workerd':

[ERROR] Error: The WASI method is not implemented
    at new WASI (node:wasi:27:15)
[ERROR] [build] Caught error rendering /example:
  Failed to prerender https://example.com/example/: The WASI method is not implemented

The WASI binding's browser entry (satteri_napi.wasi-browser.js) is not usable either — it needs top-level fetch() of the .wasm, new Worker() and a shared WebAssembly.Memory, none of which exist in workerd.

Link to Minimal Reproducible Example

https://github.com/314systems/starlight-bug

Participation

• I am willing to submit a pull request for this issue.