module.exports = {
  entry: './path/to/main.mjs',
  output: {
    filename: 'main.es5.js',
    path: path.resolve(__dirname, 'public'),
  },
  module: {
    rules: [{
      test: /\.m?js$/,
      use: {
        loader: 'babel-loader',
        options: {
          presets: [
            ['env', {
              modules: false,
              useBuiltIns: true,
              targets: {
                browsers: [
                  '> 1%',
                  'last 2 versions',
                  'Firefox ESR',
                ],
              },
            }],
          ],
        },
      },
    }],
  },
};