webpack.dev.config.js

import { fileURLToPath } from 'url';
import path, { dirname } from 'path';
import { CleanWebpackPlugin } from 'clean-webpack-plugin';
import HtmlWebpackPlugin from 'html-webpack-plugin';
import TerserPlugin from 'terser-webpack-plugin';
import CopyPlugin from 'copy-webpack-plugin';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

export default {
  mode: 'development',
  entry: './demo/index.js',
  watch: true,
  output: {
    filename: 'main.js',
    path: path.resolve(__dirname, 'dev-build'),
  },
  devServer: {
    static: path.join(__dirname, 'dev-build'),
    compress: true,
    port: 9000,
  },
  devtool: 'source-map',
  module: {
    rules: [
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader'],
      },
      {
        test: /\.js$/,
        exclude: /node_modules/,
        loader: 'babel-loader',
        resolve: {
          fullySpecified: false,
        },
      },
    ],
  },
  plugins: [
    new CleanWebpackPlugin(),
    new HtmlWebpackPlugin({ inject: true, template: './demo/index.html' }),
    new TerserPlugin({
      // Use multi-process parallel running to improve the build speed
      // Default number of concurrent runs: os.cpus().length - 1
      parallel: true,
      terserOptions: {
        sourceMap: true,
      },
    }),
    new CopyPlugin({
      patterns: [
        { from: 'src/images', to: 'images' },
        { from: 'node_modules/flag-icons/flags/4x3/', to: 'images/flags/' },
      ],
    }),
  ],
};