title: Angular + Express PWA 504 Gateway
body: <p>I'm having trouble creating a PWA angular app with NodeJS + Express server.</p>
  <ul>
  <li>I'm serving my angular build --prod on a static path in Express</li>
  <li>I'm using routes in my Angular App</li>
  <li>The client manages to load <code>manifest.json</code>, <code>ngsw-worker.js</code>, <code>ngsw.json?ngsw-cache-bust=[RANDOM]</code> and all the rest of the files</li>
  <li>The client creates an SW and shows this gear icon on every request</li>
  <li>The DevTools Disable cache checkbox is disabled ;)</li>
  </ul>
  <p>Yet, when I check the Offline checkbox in DevTools and refresh the page I get 504 on the requested route, and then a few  seconds later, a failed request from <code>ngsw-worker.js</code></p>
  <p>It's progress in my PWA app as I don't receive the Dinosaur chrome page.</p>
  <p>Thanks in advance!</p>