Use stdweb spawn_local to execute futures

[izissise]

Description

Allow to use send_future with cargo web and asmjs-unknown-emscripten target by using stdweb spawn_local future feature.

An example of using future with stdweb https://github.com/koute/stdweb/blob/master/examples/futures/src/main.rs

Context (Environment)

• Rust: v1.39.0 stable

• yew: v0.10.0

• target: asmjs-unknown-emscripten

• cargo-web: v0.6.26

[ctaggart]

I realize this is different, but some may find it useful. I just tried using the spawn_local from wasm-bindgen for a function marked #[wasm_bindgen] and it worked. I'm using yew from master branch.

https://docs.rs/wasm-bindgen-futures/0.4.5/wasm_bindgen_futures/fn.spawn_local.html
https://github.com/rustwasm/wasm-bindgen/search?q=spawn_local&unscoped_q=spawn_local

[hgzimmerman]

Oh, interesting.

Although it has since been removed and replaced with this stdweb based spawn_local in the yewtil crate, there are eventual plans to re-add a wasm-bindgen based implementation you could choose to use. This is more simple than the prior implementation, and should make gating either behind a feature flag much easier.

[ctaggart]

With async move, I was able to call emit on branch_received: Callback<String>.

    spawn_local(async move {
        let branch = get_branch().await.unwrap_throw(); // vs unwrap?
        branch_received.emit(branch);
    });

[hgzimmerman]

Since the corresponding PR in the appropriate repo was merged, I think that this issue can be closed.