Experimental "turn key" solution for wasm and rayon. This pretty much copies the pool.rs from the official example, adding some stuff.

Note Currently the library assumes your application is generated with wasm-pack using --target web --out-name index. This is because there is no way to get import.meta.url from the WASM module.

To see how to use this library, see the examples/simple/src/lib.rs. In essence all rayon calls must return a JS Promise to work correctly, so the API is:

#[wasmyon_promise]
pub fn sum_in_workers() -> i32 {
    (0..100000 as i32).into_par_iter().sum::<i32>()
}

This creates a JS wrapper function:

function sum_in_workers(): Promise<any>

The attribute parameters are passed almost as is to the wasm_bindgen, however there is few extra parameters: #[wasmyon_promise(serde)] means the result should be parsed by serde feature, and #[wasmyon_promise(serde_wasm_bindgen)] means it should be parsed by serde-wasm-bindgen crate.

Additionally, if you want to run something in a worker by yourself, you can do it like this:

run_in_worker(|| yourstuff)

It returns a Future.

To test out, go to examples/simple directory and do the following:

1. Install wasm-pack
2. Install deno for static File HTTP server, see file-server-deno.ts ¹
3. Run wasm-pack build --target web --out-name index
4. Run deno run --allow-run --allow-net --allow-read ../file-server-deno.ts simple
5. Navigate to http://localhost:8000
6. Open a DevTools to see the communication in console

It initalizes only one WebAssembly.Memory object and shares it between the workers. It also creates the thread workers within wasm-bindgen JS snippet.

• Auto scalable worker pool, so that it terminates workers when they are not being utilized for a while...
• Number of used threads (max and initial) should be configurable on the fly
• TypeScript requires work. Because js_sys::Promise isn't giving a way to type the output type. For now it's just Promise<any>. To fix this, it probably requires a patch to wasm_bindgen.

1: If you don't want Deno, you still need a file server that is capable of setting headers Cross-Origin-Opener-Policy: same-origin and Cross-Origin-Embedder-Policy: require-corp, otherwise SharedArrayBuffer is not defined. See documentation.