examples

WebAssembly - example

Create a new Rust project, such as running:

cargo new wasm-example --lib

Add the wasm-bindgen dependency to your Cargo.toml file.

In your lib.rs file, add the wasm_bindgen macro to the top of the file, and define a simple Rust function that takes two numbers and returns their sum:

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

Build your Rust code as a WebAssembly module by running the following command, which creates a WASM file called wasm-example.wasm in the target/wasm32-unknown-unknown/release/ directory:

cargo +nightly build --target wasm32-unknown-unknown --release

Finally, create a JavaScript file that loads the WASM module and calls your Rust function:

import("./wasm_example_bg.wasm").then((module) => {
  const { add } = module;
  console.log(add(1, 2)); // outputs 3
});

This JavaScript code loads the WASM module using the import() function, which is a new feature in JavaScript that allows you to dynamically load modules at runtime. Once the module is loaded, you can call your Rust function using the add variable.