title: Express middleware before response is carried out to client
body: <p>I need to modify the response data a module sends to the client, as the module uses <code>res.send</code> i can't seem to figure out a way for me to modify the data before it's carried out to the client.</p>
  
  <p>Is there any kind of middleware/event that I can use to catch the <code>res.send</code> and modify the data before its executed?</p>
  
  <p>I am aware that <code>router.use</code> exists but it's called before the <code>router.post</code> function and not before the <code>res.send</code> is sent to the client. So I need some kind of middleware which is called after the <code>router.post</code> function is done but before anything is sent to the client.</p>