webpack.config.js

const CopyPlugin = require('copy-webpack-plugin')
const path = require('path')
const spawn = require('child_process').spawnSync

module.exports = {
  context: path.resolve(__dirname, '.'),
  devtool: 'nosources-source-map',
  entry: './index.js',
  target: 'webworker',
  plugins: [
    {
      apply: compiler => {
        compiler.hooks.compilation.tap('emscripten-build', compilation => {
          let result = spawn('node', ['build.js'], { stdio: 'inherit' })

          if (result.status != 0) {
            compilation.errors.push('emscripten build failed')
          } else {
            console.log('emscripten build complete')
          }
        })
      },
    },
    new CopyPlugin([
      // we need to manually copy this instead of requiring from
      // our script source code, since wasm files are bound to global scope
      // in Workers, rather than being fetched like the browser.
      // wranglerjs also needs to see a wasm file in order for it to be sent to the api
      // correctly.
      { from: './build/module.wasm', to: './worker/module.wasm' },
    ]),
  ],
  optimization: {
      minimize: false
  },
  module: {
    rules: [
      // Emscripten JS files define a global. With `exports-loader` we can
      // load these files correctly (provided the global’s name is the same
      // as the file name).
      {
        test: /emscripten\.js$/,
        loader: 'exports-loader',
      },
    ],
  },
}