webpack.config.js

const path = require('path');
const { merge } = require('webpack-merge');
const autoprefixer = require('autoprefixer');
const CopyPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const devMode = process.env.NODE_ENV !== 'production';

const common = {
  entry: './src/index.js',
  output: {
    filename: devMode ? '[name].js' : '[name].[contenthash].js',
    path: path.resolve(__dirname, 'dist'),
    clean: true,
  },
  plugins: [
    new CopyPlugin({
      patterns: [
        {
          from: 'public',
          globOptions: {
            gitignore: true,
            ignore: ['**/index.html'],
          },
        },
      ],
    }),
    new HtmlWebpackPlugin({ template: 'public/index.html' }),
    new MiniCssExtractPlugin({
      filename: devMode ? '[name].css' : '[name].[contenthash].css',
    }),
  ],
  module: {
    rules: [
      {
        test: /\.css$/i,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader',
          {
            loader: 'postcss-loader',
            options: {
              postcssOptions: {
                plugins: [autoprefixer],
              },
            },
          },
        ],
      },
    ],
  },
};

module.exports = devMode
  ? merge(common, {
      mode: 'development',
      output: {
        filename: 'bundle.js',
        path: path.resolve(__dirname, 'dist'),
        clean: true,
      },
      devtool: 'eval',
    })
  : merge(common, {
      mode: 'production',
      output: {
        filename: 'bundle.[contenthash].js',
        path: path.resolve(__dirname, 'dist'),
        clean: true,
      },
    });