title: Mongoose find() with function
body: <p>I want to find an object in my collection which satisfies the following:
  getDistance(userDefinedPosition, positionFromDocument) == true.</p>
  
  <p>So I would like to do something like this </p>
  
  <pre><code>Users.find( getDistance(userDefinedPosition, positionFromDocument) == true, function( ... ) ) 
  </code></pre>
  
  <p>So userDefinedPosition is value while positionFromDocument is a field from inside a possible match.</p>