webpack.config.js

const webpack = require('webpack')
const TerserPlugin = require('terser-webpack-plugin')

module.exports = {
  mode: 'production',
  entry: ['./src/index.js', 'monaco-editor/esm/vs/editor/editor.worker.js'],
  output: {
    globalObject: 'self',
    filename: 'index.user.js',
    path: __dirname
  },
  module: {
    rules: [
      {
        test: /\.m?js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              '@babel/preset-env',
              [
                'minify',
                {
                  builtIns: false,
                  evaluate: false,
                  mangle: false
                }
              ]
            ],
            comments: false
          }
        }
      },
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader', 'sass-loader']
      },
      {
        test: /\.ttf$/,
        use: ['file-loader']
      }
    ]
  },
  optimization: {
    minimize: true,
    minimizer: [new TerserPlugin()]
  },
  plugins: [
    new webpack.optimize.LimitChunkCountPlugin({
      maxChunks: 1
    })
  ]
}