https://stackoverflow.com/q/57977575/1779433

package.json

{
  "name": "smartweb-version-2",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "build": "rm -rf dist && webpack --mode development --config webpack.server.config.js && webpack --mode development --config webpack.dev.config.js",
    "start": "node ./server/app.js"
  },
  "engines": {
    "node": ">= 8.0.0",
    "npm": ">= 3.0.0"
  },
  "dependencies": {
    "axios": "^0.19.0",
    "cookie-parser": "~1.4.4",
    "debug": "~2.6.9",
    "ejs": "~2.6.1",
    "eslint": "^6.4.0",
    "eslint-config-airbnb-base": "^14.0.0",
    "eslint-plugin-import": "^2.18.2",
    "eslint-plugin-node": "^10.0.0",
    "expose-loader": "^0.7.5",
    "express": "~4.16.1",
    "http-errors": "~1.6.3",
    "jquery": "^3.4.1",
    "morgan": "~1.9.1"
  },
  "devDependencies": {
    "@babel/core": "^7.3.4",
    "@babel/preset-env": "^7.3.4",
    "autoprefixer": "^9.4.10",
    "babel-eslint": "^10.0.3",
    "babel-loader": "^8.0.5",
    "copy-webpack-plugin": "^5.0.4",
    "css-loader": "^2.1.1",
    "cssnano": "^4.1.10",
    "expose-loader": "^0.7.5",
    "file-loader": "^3.0.1",
    "img-loader": "^3.0.1",
    "mini-css-extract-plugin": "^0.5.0",
    "optimize-css-assets-webpack-plugin": "^5.0.3",
    "postcss-loader": "^3.0.0",
    "sass": "^1.17.2",
    "sass-loader": "^7.1.0",
    "uglifyjs-webpack-plugin": "^2.2.0",
    "url-loader": "^2.1.0",
    "webpack": "^4.29.6",
    "webpack-cli": "^3.2.3",
    "webpack-dev-middleware": "^3.7.0",
    "webpack-dev-server": "^3.8.1",
    "webpack-hot-middleware": "^2.25.0",
    "webpack-node-externals": "^1.7.2"
  }
}

webpack.dev.config.js

/* eslint-disable global-require */
/* eslint-disable import/no-extraneous-dependencies */
const path = require('path');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const webpack = require('webpack');

module.exports = {
  entry: {
    main: './public/index.js',
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js',
    publicPath: '/',
  },
  mode: 'development',
  target: 'web',
  devtool: '#source-map',
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: false, // set to true if you want JS source maps
      }),
      new OptimizeCSSAssetsPlugin({}),
    ],
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules)/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env'],
          },
        },
      },
      {
        test: /\.(sa|sc|c)ss$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader,
          },
          {
            loader: 'css-loader',
          },
          {
            loader: 'postcss-loader',
          },
          {
            loader: 'sass-loader',
            options: {
              implementation: require('sass'),
            },
          },
        ],
      },
      { test: /\.(png|woff|woff2|eot|ttf|svg)$/, loader: 'url-loader?limit=100000' },
      {
        // Exposes jQuery for use outside Webpack build
        test: require.resolve('jquery'),
        use: [{
          loader: 'expose-loader',
          options: 'jQuery',
        }, {
          loader: 'expose-loader',
          options: '$',
        }],
      },
    ],
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: 'bundle.css',
    }),
    new CopyWebpackPlugin([
      { from: './public/img', to: 'img' },
    ]),
    new webpack.ProvidePlugin({
      $: 'jquery',
      jQuery: 'jquery',
      'window.jQuery': 'jquery',
    }),
    new webpack.optimize.OccurrenceOrderPlugin(),
    new webpack.HotModuleReplacementPlugin(),
    new webpack.NoEmitOnErrorsPlugin(),
  ],
};

webpack.server.config.js

/* eslint-disable no-fallthrough */
/* eslint-disable import/no-extraneous-dependencies */
/* eslint-disable import/order */
/* eslint-disable no-use-before-define */
/* eslint-disable no-process-exit */
/**
 * Module dependencies.
 */

const app = require('express')();
const debug = require('debug')('smartweb-version-2:server');
const http = require('http');
const webpack = require('webpack');
const webpackDevMiddleware = require('webpack-dev-middleware');
const webpackHotMiddleware = require('webpack-hot-middleware');
const config = require('./webpack.dev.config.js');

/**
 * Get port from environment and store in Express.
 */
const compiler = webpack(config);
const port = normalizePort(process.env.PORT || '3000');
app.set('port', port);
app.use(webpackDevMiddleware(compiler, {
  noInfo: true, publicPath: config.output.publicPath,
}));
app.use(webpackHotMiddleware(compiler));
/**
 * Create HTTP server.
 */

const server = http.createServer(app);

/**
 * Listen on provided port, on all network interfaces.
 */

server.listen(port);
server.on('error', onError);
server.on('listening', onListening);

/**
 * Normalize a port into a number, string, or false.
 */

function normalizePort(val) {
  const port = parseInt(val, 10);

  if (isNaN(port)) {
    // named pipe
    return val;
  }

  if (port >= 0) {
    // port number
    return port;
  }

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 */

function onError(error) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  const bind = typeof port === 'string'
    ? `Pipe ${port}`
    : `Port ${port}`;

  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      console.error(`${bind} requires elevated privileges`);
      process.exit(1);
    case 'EADDRINUSE':
      console.error(`${bind} is already in use`);
      process.exit(1);
    default:
      throw error;
  }
}

/**
 * Event listener for HTTP server "listening" event.
 */

function onListening() {
  const addr = server.address();
  const bind = typeof addr === 'string'
    ? `pipe ${addr}`
    : `port ${addr.port}`;
  debug(`Listening on ${bind}`);
}