redux-devtools/extension/examples/counter/server.js

var webpack = require('webpack');
var webpackDevMiddleware = require('webpack-dev-middleware');
var webpackHotMiddleware = require('webpack-hot-middleware');
var config = require('./webpack.config');

var app = new require('express')();
var port = 4001;

var compiler = webpack(config);
app.use(
  webpackDevMiddleware(compiler, {
    noInfo: true,
    publicPath: config.output.publicPath,
  })
);
app.use(webpackHotMiddleware(compiler));

app.get('/', function (req, res) {
  res.sendFile(__dirname + '/index.html');
});

app.listen(port, function (error) {
  if (error) {
    console.error(error);
  } else {
    console.info(
      '==> 🌎  Listening on port %s. Open up http://localhost:%s/ in your browser.',
      port,
      port
    );
  }
});