WebAssembly support

Deno can execute WebAssembly modules with the same interfaces that browsers provide.

// This WASM binary exports a `main` function that just returns `42` upon
// invocation.
const wasmCode = new Uint8Array([
  0, 97, 115, 109, 1, 0, 0, 0, 1, 133, 128, 128, 128, 0, 1, 96, 0, 1, 127,
  3, 130, 128, 128, 128, 0, 1, 0, 4, 132, 128, 128, 128, 0, 1, 112, 0, 0,
  5, 131, 128, 128, 128, 0, 1, 0, 1, 6, 129, 128, 128, 128, 0, 0, 7, 145,
  128, 128, 128, 0, 2, 6, 109, 101, 109, 111, 114, 121, 2, 0, 4, 109, 97,
  105, 110, 0, 0, 10, 138, 128, 128, 128, 0, 1, 132, 128, 128, 128, 0, 0,
  65, 42, 11
]);
const wasmModule = new WebAssembly.Module(wasmCode);
const wasmInstance = new WebAssembly.Instance(wasmModule);
const main = wasmInstance.exports.main as CallableFunction
console.log(main().toString());

Loading from files:

const wasmCode = await Deno.readFile("main.wasm");
const wasmModule = new WebAssembly.Module(wasmCode);
const wasmInstance = new WebAssembly.Instance(wasmModule);
const main = wasmInstance.exports.main as CallableFunction;
console.log(main().toString());

And for loading WebAssembly modules over the network (note that the file must be served with application/wasm MIME type):

const { instance, module } = await WebAssembly.instantiateStreaming(
  fetch("https://wpt.live/wasm/incrementer.wasm"),
);
const increment = instance.exports.increment as (input: number) => number;
console.log(increment(41));