webpack.prod.js

const path = require('path');
const merge = require('webpack-merge'); // eslint-disable-line import/no-extraneous-dependencies
const { CleanWebpackPlugin } = require('clean-webpack-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const MiniCssExtractPlugin = require('mini-css-extract-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const TerserPlugin = require('terser-webpack-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const HtmlWebpackPlugin = require('html-webpack-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const CopyPlugin = require('copy-webpack-plugin'); // eslint-disable-line import/no-extraneous-dependencies
const common = require('./webpack.common');

module.exports = merge(common, {
  mode: 'production',
  output: {
    filename: '[name].[contentHash].bundle.js',
    path: path.resolve(__dirname, 'dist'),
  },
  optimization: {
    minimizer: [
      new OptimizeCssAssetsPlugin(),
      new TerserPlugin(),
      new HtmlWebpackPlugin({
        template: './src/template.html',
        minify: {
          removeAttributeQuotes: true,
          collapseWhitespace: true,
          removeComments: true,
        },
      }),
    ],
  },
  plugins: [
    new MiniCssExtractPlugin({ filename: '[name].[contentHash].css' }),
    new CleanWebpackPlugin(),
    new CopyPlugin({
      patterns: [
        { from: './src/assets', to: 'src/assets' },
      ],
    }),
  ],
  module: {
    rules: [
      {
        test: /\.scss$/,
        use: [
          MiniCssExtractPlugin.loader, // 3. Extract css into files
          'css-loader', // 2. Turns css into commonjs
          'sass-loader', // 1. Turns sass into css
        ],
      },
    ],
  },
});