server.js

const express = require('express');
const { join } = require('path');
const { parse } = require('url');
const compression = require('compression');
const next = require('next');
// const Cookies = require("universal-cookie");

const routes = require('./routes');

const port = process.env.PORT || 3000;
const app = next({ dev: process.env.NODE_ENV !== 'production' });
const handle = app.getRequestHandler();

app
  .prepare()
  .then(() => {
    const server = express();

    // Serve as GZIP
    server.use(compression());

    server.get('/service-worker.js', (req, res) => {
      // const filePath = path.resolve('service-worker.js');
      const parsedUrl = parse(req.url, true);
      const { pathname } = parsedUrl;
      const filePath = join(__dirname, '.next/static/', pathname);
      res.setHeader(
        'Cache-Control',
        'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0',
      );
      // adding no-caching for service worker
      // Don't cache service worker is a best practice
      // Clients wont get emergency bug fixes etc.
      res.set('Content-Type', 'application/javascript');
      // res.setHeader('Clear-Site-Data', 'cookies, cache'); // adding kill-switch during new deployment, if you want
      app.serveStatic(req, res, filePath);
    });
    const handler = routes.getRequestHandler(
      app,
      ({ req, res, route, query }) => {
        app.render(req, res, route.page, query);
      },
    );
    server.use(handler);
    server.get('*', (req, res) => handle(req, res));
    server.listen(port, err => {
      if (err) throw err;
      console.log(`> Ready on http://localhost:${port}`);
    });
  })
  .catch(err => {
    console.error(err.stack);
    process.exit(1);
  });