title: Mongoose find max value of a field with hexadecimal value
body: <p>I have a field <code>code</code> that contains a value in hexadecimal.</p>
  
  <p>How can I get the highest value in the collection in one mongoose query?</p>
  
  <p>If I have several collection with the same field <code>code</code>, is there a way to get the highest value based on all the collections in one request?</p>