linecode/winterjs

Winter is coming... ❄️

WinterJS

A blazing-fast JavaScript server that runs Service Workers scripts according to the Winter Community Group specification.

WinterJS is able to handle up to 100,000 reqs/s in a single laptop (see Benchmark).

Note: WinterJS is not officially endorsed by WinterCG, despite sharing "Winter" in their name. There are many runtimes supporting WinterCG, WinterJS being one among those.

Running WinterJS with Wasmer

The WinterJS server is published in Wasmer as wasmer/winterjs.

You can run the HTTP server locally with:

wasmer run wasmer/winterjs --net --mapdir=tests:tests tests/simple.js

Where simple.js is:

addEventListener('fetch', (req) => {
  req.respondWith(new Response('hello'));
});

Running WinterJS Natively

You can run WinterJS natively by simply doing

cargo run -- tests/simple.js

And then access the server in https://localhost:8080/

How WasmerJS works

WinterJS is powered by SpiderMonkey, Spiderfire and hyper to bring a new level of awesomeness to your Javascript apps.

WinterJS is using the WASIX standard to compile to WebAssembly. Please note that compiling to WASIX is currently a complex process. We recommend using precompiled versions from wasmer/winterjs, but please open an issue if you need to compile to WASIX locally.

Limitations

WinterJS is early, pre-release software. It is currently not fully compliant with the WinterCG spec and the runtime itself is still a work in progress. It is not recommended to use WinterJS in production yet. For more information, see the API Compatibility section below.

WinterCG API Compatibility

This section will be updated as APIs are added/fixed. If an API is missing from this section, that means that it is still not implemented.

The following words are used to describe the status of an API:

• ✅ Stable - The API is implemented and fully compliant with the spec. This does not account for potential undiscovered implementation errors in the native code.
• 🔶 Partial - The API is implemented but not fully compliant with the spec and/or there are known limitations.
• ❌ Pending - The API is not implemented yet.

API	Status	Notes
console	✅ Stable
fetch	🔶 Partial	Request, Response and ReadableStream need to be stabilized before fetch can be considered Stable
URL	✅ Stable
URLSearchParams	✅ Stable
Request	🔶 Partial	ReadableStream needs to be stabilized before Request can be considered Stable Requests cannot be sent with ReadableStream bodies
Headers	✅ Stable
Response	🔶 Partial	ReadableStream needs to be stabilized before Response can be considered Stable. Response.body returns a Promise that resolves to a ReadableStream instead of returning a ReadableStream directly.
Blob	🔶 Partial	Blob.stream() is not implemented yet
FormData	✅ Stable
TextDecoder	🔶 Partial	Only UTF-8 is supported
TextEncoder	🔶 Partial	Only UTF-8 is supported
ReadableStream	🔶 Partial	Creating ReadableStreams with type: 'bytes' is not supported yet. Returning ReadableStreams to native code is not supported yet.
atob	✅ Stable
btoa	✅ Stable
performance.now()	✅ Stable
performance.timeOrigin	❌ Pending