initThreadPool freezing after call

I’m trying to make the basic example with the sum function work

#[wasm_bindgen]
pub fn sum(numbers: &[i32]) -> i32 {
    numbers.par_iter().sum()
}

but every time when JS hit the funcion initThreadPool(even with the init function working correctly), he’s freezing, I have tried in two different ways, first

init().then(_ => {
    initThreadPool(navigator.hardwareConcurrency).then(_ => {
        sum(new Int32Array([1, 2, 3]))
    })
})

and

init().then(_ => {
    initThreadPool(navigator.hardwareConcurrency);
    sum(new Int32Array([1, 2, 3]));
})

but with that last way, I always get that error: “panicked at ‘The global thread pool has not been initialized.: ThreadPoolBuildError { kind: IOError(Error { kind: Unsupported, message: “operation not supported on this platform” }) }’”, and after a few days I still have no idea what it could be

[RReverser]

@ranis-junior Wait a second, so you’re trying to use wasm-bindgen generated code directly from HTML, aka from the main thread? Unfortunately that won’t work due to Wasm limitations intended to avoid blocking the main thread.

Please check the Caveats section of the docs as well as how the demo does it - you must do all the work in a dedicated Worker.

Even if you don’t use Comlink, the minimal example should be more like:

1. worker.js:

import init, {sum, initThreadPool} from "/static/pkg/sum.js";

init().then(_ => {
    initThreadPool(navigator.hardwareConcurrency).then(_ => {
        let result = sum(new Int32Array([1, 2, 3]))
        console.log(result)
    })
})

1. index.html:

<script type="module">
new Worker(new URL('worker.js', import.meta.url), { type: 'module' });
</script>

It’s surprising that you didn’t see an error message in the Console, both Chrome and Firefox should complain when you’re trying to use Wasm threads from the main browser thread.

[RReverser]

Glad it worked!