express.js

import express from 'express';
import compression from 'compression';
import browserCapabilities from 'browser-capabilities';
import {UAParser} from 'ua-parser-js';
import {fileURLToPath} from 'url';
import {dirname} from 'path';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

const app = express();
const basedir = __dirname + '/src/';

function getSourcesPath(request, filePath = '') {
  const userAgent = request.headers['user-agent'];
  const clientCapabilities = browserCapabilities.browserCapabilities(userAgent);
  const browserName = new UAParser(userAgent).getBrowser().name || '';
  // skip Edge because browser-capabilities library is outdated
  const needToUpgrade = !clientCapabilities.has('modules') && browserName !== 'Edge';
  return needToUpgrade ? `${basedir}upgrade-browser.html` : `${basedir}${filePath}`;
}

app.use(compression());

app.use('/menu/', (req, res, next) => {
  express.static(getSourcesPath(req))(req, res, next);
});

app.get(/.*service-worker\.js/, function (req, res) {
  res.sendFile(getSourcesPath(req) + 'service-worker.js');
});

app.use((req, res) => {
  res.header('Cache-Control', 'private, no-cache, no-store, must-revalidate');
  res.header('Expires', '-1');
  res.header('Pragma', 'no-cache');
  res.sendFile(getSourcesPath(req) + 'index.html');
});

app.listen(8080);