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

#![feature(use_extern_macros, wasm_import_module)]

extern crate wasm_bindgen;

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
extern "C" {
    #[wasm_bindgen(js_namespace = console)]
    fn log(s: &str);
    #[wasm_bindgen(js_namespace = console, js_name = log)]
    fn log_u32(a: u32);
    #[wasm_bindgen(js_namespace = console, js_name = log)]
    fn log_many(a: &str, b: &str);
}

#[wasm_bindgen]
pub fn run() {
    log("Hello from Rust!");
    log_u32(42);
    log_many("Logging", "many values!");
}