title: Express JS - Static files not being served from cache
body: <p>I'm running an application on Express and my browser keeps fetching files that should've already been cached. The status code for the offending files is 304 and size is consistently 220 B / 221 B. Other resources (that are getting served properly), are showing '(from cache)'.</p>
  <p>A bit more information: the ETags / file contents haven't changed and I've set some response headers.</p>
  <pre><code>    res.set('Cache-Control', 'max-age=345600');
      res.set('Expires', new Date(Date.now() + 345600000).toUTCString());
  </code></pre>
  <p><a href="https://i.stack.imgur.com/50ZbI.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/50ZbI.jpg" alt="Cache Fail" /></a><br />
  <sub>(source: <a href="http://www.imageno.com/image.php?id=mekl0pw40qr5&amp;kk=619682137" rel="nofollow noreferrer">imageno.com</a>)</sub></p>
  <p>Admittedly, I'm no HTTP expert, but maybe someone can help me understand why this might be happening?</p>