WinterJS runtime support

[pi0]

Related: Wasmer Edge

WinterJS is a JavaScript Service Workers server written in Rust, that uses the SpiderMonkey runtime to execute JavaScript (the same runtime that Firefox uses) (announcement).

The latest documentation is living in: https://nitro.unjs.io/deploy/runtimes/winterjs

Changelog

• Initial support (POC): feat: add experimental winterjs preset #1863
• 0.1.7 compatibility with respondWith: fix(winterjs): 0.1.7 compatibility #1876

Status

Currently, winter is not a stable preset but having it in the nightly channel allows iterating and testing across the ecosystem.

Currently, Nitro tests are passing (9 skipped mainly because of isolated behavior)

nitro-deploys works except for static assets

Basic Nuxt apps used to hang are now working too!

TODO:

• Using plain handler format as current runtime is not completely web compatible (or h3 is faulty!)
• Headers.entities poly-filled using array iterator (tracker: Missing Headers.entries wasmerio/winterjs#25)
• URL.pathname poly-filled and returns this.path (tracker: Missing URL.pathname wasmerio/winterjs#26)
• Added support for new URL(url, base) using ufo utils and a polyfill (Cannot construct URL with base wasmerio/winterjs#27)
• Using inlined serve static as there is no info on how to integrate with filesystem API for static asset handling (IMPORTANT LIMITATION) (raised question ~> Serving assets from filesystem wasmerio/winterjs#28)
• Response.body getter overridden to return bodyInit (this is an ugly workaround to fix issue when body getter is Promise<ReadableStream> and also non iteratable. used by proxy streaming. (seems known issue?)

[pi0]

Update: Before 2.8 release I just noticed runtime is completely broken again. I had to disable tests to allow release and also hide documentation temporarily. (preset will be still available for 2.8 but undocumented and unsupported)

Really looking forward to announce wasmer support but seems too early.