Rust WebAssembly loader

Usage

This is a simple Webpack loader that shells out to cargo to build a Rust project targeting WebAssembly. See this post for more details on using Rust to target the web.

To use it, first install the package:

$ npm install rust-wasm-loader

Configure the loader in your Webpack config:

module.exports = {
  // ...
  module: {
    rules: [
      {
        test: /\.rs$/,
        use: {
          loader: 'rust-wasm-loader',
          options: {
            // Path to your 'build' or 'dist' directory relative to project root
            path: 'build/',
          }
        }
      },
      // ...
    ]
  }
}

Note: if you are using file-loader, make sure to add .wasm to the test field, otherwise the module will not be copied! (e.g. test: /\.(wasm|jpg|jpeg|png|gif|svg|eot|ttf|woff|woff2)$/i,).

Make sure you have the cargo, rustc, and (optionally) emsdk binaries somewhere in your PATH. stdweb and other Rust libraries require a nightly build, which can be installed from https://rustup.rs/ .

Require and initialize the wasm module:

const wasm = require('./lib.rs')
wasm.then(module => {
  // Use your module here
  console.log(module.doub(21))
})

or with async/await:

async function loadwasm() {
  const lib = await require('./lib.rs');
  // Use your module here
  console.log(lib.doub(21));
}
loadwasm();

Configuration

The following options can be added to the Webpack loader query:

Name	Description	Required	Default
release	Whether or not to pass the --release flag to cargo	false	false
path	Path to your webpack output folder relative to project root	true	''
target	Allows one to specify wasm32-unknown-emscripten as build target	false	'wasm32-unknown-unknown'

Example

Check out the example directory for a simple Hello World example.

This project is based off of rust-emscripten-loader by mrdziuban.