wasm-bindgen/examples/import_js/src/lib.rs

extern crate wasm_bindgen;

use wasm_bindgen::prelude::*;

#[wasm_bindgen(module = "./defined-in-js")]
extern "C" {
    fn name() -> String;

    type MyClass;

    #[wasm_bindgen(constructor)]
    fn new() -> MyClass;

    #[wasm_bindgen(method, getter)]
    fn number(this: &MyClass) -> u32;
    #[wasm_bindgen(method, setter)]
    fn set_number(this: &MyClass, number: u32) -> MyClass;
    #[wasm_bindgen(method)]
    fn render(this: &MyClass) -> String;
}

// Import `console.log` so we can log something to the console
#[wasm_bindgen]
extern "C" {
    #[wasm_bindgen(js_namespace = console)]
    fn log(s: &str);
}

#[wasm_bindgen]
pub fn run() {
    log(&format!("Hello, {}!", name()));

    let x = MyClass::new();
    assert_eq!(x.number(), 42);
    x.set_number(10);
    log(&x.render());
}