Best practices for providing non-blocking JS bindings

[svenpilz]

Hi!

I'm looking for best practices to provide non-blocking calls to long running computations. Right now we instantiate the WASM module in a new web-worker and use message passing and promises to call functions. Which works, but we need some boilerplate code for this to work.

Does Emscripten support to always wrap function calls with a promise and execute them in a separate worker? Something like PROXY_TO_PTHREAD but for functions? No reentrance and only a single worker with synchronous execution inside.

Thanks and greetings from Berlin
Sven

[sbc100]

Good question. I'm not sure we have anything out-of-the box that does this. We do provide a lot of the pieces to build it yourself (i.e. proxying.h and promise.h), but maybe its something we could add more directly. @tlively WDYT?

[tlively]

emscripten_proxy_promise sounds like it's 90% of what is needed here. It's not yet documented, but it should be stable and you can find it in proxying.h. The API to use the returned em_promise_t is in promise.h. The only thing you'd have to do yourself is spawn a thread and create proxying queue to send work to it.