webpack.config.js

const path = require('path');
const copy = require('copy-webpack-plugin');

module.exports = {
  mode: 'production',
  entry: {
    controller: './extension/controller.js',
    ldn: './extension/ldn.js',
    popup: './extension/popup.js'
  },
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: '[name].bundle.js'
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env']
          }
        }
      }
    ]
  },
  plugins: [
    new copy([
      { from: 'extension/popup.html', to: 'popup.html' },
      { from: 'extension/manifest.json', to: 'manifest.json' },
      { from: 'extension/loader.js', to: 'loader.js' },
      { from: 'extension/styles', to: 'styles' },
      { from: 'extension/scripts', to: 'scripts' }
    ])
  ]
};