add js_class attribute for defining what class an imported method is for

[kzvi]

Allows this to work:

#[wasm_bindgen]
extern {
    #[wasm_bindgen(js_name = String)]
    pub type JsString;

    #[wasm_bindgen(method, js_class = "String")] // <-- here
    pub fn slice(this: &JsString, start: u32, end: u32) -> JsString;
}


#[wasm_bindgen]
pub fn f(x: JsString) -> JsString {
    x.slice(1, 3)
}

[fitzgen]

These changes look great!

But before we merge this, can you add test coverage for this? A great way to do that would be to add the JsString bindings from your comment to src/js.rs and a corresponding test to tests/all/js_globals/JsString.rs similar to Array.rs in that same directory.

Thanks again @kzvi :)

[kzvi]

Done.

[ohanar]

Great thanks @kzvi.