server.js

/**
 * Setup and run the development server for Hot-Module-Replacement
 * https://webpack.github.io/docs/hot-module-replacement-with-webpack.html
 */

const express = require("express");
const webpack = require("webpack");
const webpackDevMiddleware = require("webpack-dev-middleware");
const webpackHotMiddleware = require("webpack-hot-middleware");
const { spawn } = require("child_process");

const config = require("./webpack.config.development");

const argv = require("minimist")(process.argv.slice(2));

const app = express();
const compiler = webpack(config);
const PORT = process.env.PORT || 3000;

const wdm = webpackDevMiddleware(compiler, {
  publicPath: config.output.publicPath,
  stats: {
    colors: true
  }
});

app.use(wdm);

app.use(webpackHotMiddleware(compiler));

const server = app.listen(PORT, "localhost", serverError => {
  if (serverError) {
    return console.error(serverError);
  }

  if (argv["start-hot"]) {
    spawn("npm", ["run", "start-hot"], { shell: true, env: process.env, stdio: "inherit" })
      .on("close", code => process.exit(code))
      .on("error", spawnError => console.error(spawnError));
  }

  console.log(`Listening at http://localhost:${PORT}`);
});

process.on("SIGTERM", () => {
  console.log("Stopping dev server");
  wdm.close();
  server.close(() => {
    process.exit(0);
  });
});