webpack.config.js

const HtmlWebpackPlugin = require('html-webpack-plugin');
const {CleanWebpackPlugin} = require('clean-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const path = require('path');

const isProduction = process.env.NODE_ENV === 'production';

module.exports = {
  mode: isProduction ? 'production' : 'development',
  devtool: isProduction ? false : 'source-map',
  entry: ['./src/js/script.js', './src/sass/master.sass'],
  output: {
    path: path.resolve(__dirname, './dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: [/node_modules/],
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              ['@babel/preset-env', {useBuiltIns: 'usage', corejs: 3}],
            ],
          },
        },
      },
      {
        test: /\.sass$/,
        use: [
          MiniCssExtractPlugin.loader,
          {
            loader: 'css-loader?-url',
          },
          {
            loader: 'postcss-loader',
            options: {
              postcssOptions: {
                plugins: [['postcss-preset-env']],
              },
            },
          },
          {
            loader: 'sass-loader',
          },
        ],
      },
      {
        test: /\.mp3$/,
        use: [
          {
            loader: 'file-loader',
            options: {
              name: '[name].[ext]',
              esModule: false,
            },
          },
        ],
      },
    ],
  },
  plugins: [
    new CleanWebpackPlugin(),
    new HtmlWebpackPlugin({
      template: path.resolve(__dirname, './src/html/index.html'),
    }),
    new MiniCssExtractPlugin(),
  ],
  devServer: {
    // Send 404s to index.html, which mimics what `.htaccess` does.
    historyApiFallback: true,
  },
};