Hello World

For a quick start, create a new node project with a package.json as you normally would and follow these steps:

Note: There's also asinit that can do most of this for you automatically.

Step 1

Install AssemblyScript as a development dependency by pointing npm at the GitHub repository (for now)

$> npm install --save-dev AssemblyScript/assemblyscript

and create a new top-level directory assembly/ for your AssemblyScript sources

$> mkdir assembly

that contains the following tsconfig.json

{
  "extends": "../node_modules/assemblyscript/std/assembly.json",
  "include": [
    "./**/*.ts"
  ]
}

plus the following exemplary module.ts entry file:

export function add(a: i32, b: i32): i32 {
  return a + b;
}

Step 2

Set up a build command by adding the following to your package.json in your project's root directory

  "scripts": {
    "build": "npm run build:untouched && npm run build:optimized",
    "build:untouched": "asc assembly/module.ts -t module.untouched.wat -b module.untouched.wasm --validate --sourceMap --measure",
    "build:optimized": "asc assembly/module.ts -t module.optimized.wat -b module.optimized.wasm --validate --sourceMap --measure --optimize"
   }

and run

$> npm run build

to compile the entry file to both an untouched and an optimized WebAssembly binary (here: also text format and a source map).

Note: If the build fails, it might be necessary (at this point) to npm install --save-dev ts-node.

Step 3

Add a new file module.js in your project's root directory

const fs = require("fs");
module.exports = new WebAssembly.Instance(new WebAssembly.Module(fs.readFileSync(__dirname + "/module.optimized.wasm"), {})).exports;

And that's it! This file allows you to use your WebAssembly module like any other node module, like so:

var myModule = require("./module.js");
console.log(myModule.add(1, 2));

See the other pages of the wiki for additional information. Happy coding!