server.js

const express = require('express');
const webpack = require('webpack');
const webpackDevMiddleware = require('webpack-dev-middleware');
const config = require('./webpack.dev.config.js');

const app = express();
const compiler = webpack(config);

// Tell express to use the webpack-dev-middleware and use the webpack.config.js
// configuration file as a base.
app.use(webpackDevMiddleware(compiler, {
  publicPath: config.output.publicPath,
}));

// Serve the files on port 3000.
app.listen(3000, function () {
  console.log('Example app listening on port 3000!\n');
});