Use node_modules (Node.js) in WASM ?

[goriunov]

The question is pretty much title.

As example suppose i have node_modules which creates a WebSocket will say ws js is there a way i can pass it to the WASM and use it inside Rust code ?

And is there a way to pass function from JS to Rust (callback).

Thank you very much :)

[fitzgen]

Here are a few links to docs that should help you out:

https://rustwasm.github.io/wasm-bindgen/reference/receiving-js-closures-in-rust.html
https://rustwasm.github.io/wasm-bindgen/examples/closures.html
https://rustwasm.github.io/wasm-bindgen/api/web_sys/struct.WebSocket.html

Does this answer your question?

[goriunov]

I have went thought links and found #[wasm_bindgen(module = "./defined-in-js")] of importing js code, will this work on node_modules ? For example :

#[wasm_bindgen(module = "crypto")]

or

#[wasm_bindgen(module = "https")]

[Pauan]

@goriunov Yes, it will work.

Also, take a look at wasm-pack, which is a tool that makes it easy to create npm packages with Rust (including importing other npm packages). It internally runs wasm-bindgen.

[goriunov]

That is a very good help. Thank you ;) I have also one more question. I have just started with WASM RUST and kind of confused about one thing.

How do i add to external c this kinda thing from js native.client.group.create(0);

I know that create(0) can be represented as

extern "C" {
  fn create(a: u32) -> JsValue;
}

but what if i want to export only native from js and then call that long chain. The farthest i went is:

extern "C" {
// This is completely wrong thing but now 
// i can access `client` but how do i get `group` and `create` function from there
 #[wasm_bindgen(js_namespace = native)]
  // fn client() -> JsValue; 
}

I would really appreciate if you could help me this one. Thank you.

[alexcrichton]

@goriunov for that you may be intersted in --

• https://rustwasm.github.io/wasm-bindgen/reference/accessing-properties-of-untyped-js-values.html
• https://rustwasm.github.io/wasm-bindgen/reference/working-with-duck-typed-interfaces.html

Does that help?

[Pauan]

@alexcrichton I think they're trying to do something like this:

#[wasm_bindgen]
extern {
    #[wasm_bindgen(js_namespace = "native.client.group")]
    fn create(a: u32) -> JsValue;
}

But that doesn't seem to work right now.

[Pauan]

@goriunov There might be a better way to do this, but this was the best way that I could come up with:

#[wasm_bindgen]
extern {
    type Group;

    #[wasm_bindgen(method, structural)]
    fn create(this: &Group, a: u32) -> JsValue;
}

#[wasm_bindgen]
extern {
    type Client;

    #[wasm_bindgen(method, structural, getter)]
    fn group(this: &Client) -> Group;
}

#[wasm_bindgen]
extern {
    type Native;

    #[wasm_bindgen(method, structural, getter)]
    fn client(this: &Native) -> Client;
}

#[wasm_bindgen]
extern {
    static native: Native;
}

Here's an example of how to use it:

let output = native.client().group().create(0);

[goriunov]

Would be really good to have

#[wasm_bindgen]
extern {
    #[wasm_bindgen(js_namespace = "native.client.group")]
    fn create(a: u32) -> JsValue;
}

solution, but second one is alright too :)
Thank you very much for your help.

[alexcrichton]

I'm going to close this as I think it's possible to do so today with wasm-bindgen, and I think rustwasm/rfcs#8 and rustwasm/rfcs#6 also help here quite a lot.