webpack.config.js

const path = require('path');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
  entry: path.resolve(__dirname, './src/app.js'),
  module: {
    rules: [
      {
        test: /\.css$/i,
        use: [
          {
            loader: MiniCssExtractPlugin.loader,
          },
          'css-loader',
        ],
      },
      {
        test: /\.m?js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              ['@babel/preset-env', {
                targets: {
                  ie: "11"
                }
              }]
            ]
          }
        }
      }
    ],
  },
  output: {
    filename: 'app.js',
    path: path.resolve(__dirname, './app/assets'),
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: 'app.css'
    }),
  ],
};