Rust/Webassembly/wasm-bindgen - getting values from `js_sys' Promise

Question

I'm playing with wasm-bindgen ( https://github.com/rustwasm/wasm-bindgen ), just out of curiosity.

While playing with the Navigator (web_sys crate) I stumbled upon this method:

https://docs.rs/web-sys/0.3.36/web_sys/struct.MediaDevices.html#method.enumerate_devices

it returns a Result..now, I'm new to Rust, and my question is how can I fetch the value of the Promise?

How the Closure::wrap works? How to use it with then method to fetch the results?

I wonder if someone could be so kind to explain me how to deal with Promise

Here an example that returns a Promise:

let window = web_sys::window().expect("no global `window` exists");
let navigator = window.navigator();

if let Ok(devs) = navigator.media_devices() {
   if let Ok(prom) = devs.enumerate_devices() {
        //..??? how to list all devices 
   }
}

All the best, Luca

user_1257094 · Answer

There is official documentation available on the wasm-bindgen site.

In short, you can use wasm_bindgen_futures::JsFuture::from(promise).await? to retrieve the result of the promise and continue working with the usual Rust async functionality.

Rust/Webassembly/wasm-bindgen - getting values from `js_sys' Promise

1 Answers