package.json

{
  "name": "demo15",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "webpack serve --open --config webpack.dev.js",
    "build": "webpack --config webpack.prod.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "css-loader": "^6.7.1",
    "html-webpack-plugin": "^5.5.0",
    "mini-css-extract-plugin": "^2.6.0",
    "style-loader": "^3.3.1",
    "webpack": "^5.72.0",
    "webpack-cli": "^4.9.2",
    "webpack-dev-server": "^4.8.1",
    "webpack-merge": "^5.8.0"
  }
}

webpack.common.js

const path = require('path')
const HtmlWebpackPlugin = require('html-webpack-plugin')

module.exports = {
  entry: {
    app: './src/app.js'
  },
  output: {
    filename: '[name].bundle.js',
    chunkFilename: '[name].chunk.js',
    path: path.resolve(__dirname, 'dist'),
    clean: true
  },
  module: {
    rules: [
      {
        test: /\.(png|svg|jpg|jpeg|gif)$/i,
        type: 'asset/resource'
      },
      {
        test: /\.(woff|woff2|eot|ttf|otf)$/i,
        type: 'asset/resource'
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: 'Production'
    })
  ],
  optimization: {
    runtimeChunk: 'single',
    splitChunks: {
      cacheGroups: {
        vendor: {
          chunks: 'all',
          test: /[\\/]node_modules[\\/]/,
          name: 'vendor'
        }
      }
    }
  }
}

webpack.prod.js

const { merge } = require('webpack-merge')
const common = require('./webpack.common.js')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')

module.exports = merge(common, {
  mode: 'production',
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader']
      }
    ]
  },
  plugins: [
    new MiniCssExtractPlugin()
  ]
})

webpack.dev.js

const { merge } = require('webpack-merge')
const common = require('./webpack.common.js')

module.exports = merge(common, {
  mode: 'development',
  devtool: 'eval-source-map',
  devServer: {
    hot: true,
    historyApiFallback: true,
    client: {
      overlay: true
    }
  },
  module: {
    rules: [
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader']
      }
    ]
  }
})