title: MongoDB $where query with white space in field name
body: <p>I'm using MongoDB to make a $where request, as follow:</p>
  
  <pre><code>db.statistiquesClients.find({$where : function() { return (this.postal code == "123 456")}})
  </code></pre>
  
  <p>As you can see, the field postal code has a space, hence this request doesn't work and the error is:</p>
  
  <pre><code>2018-12-18T21:28:57.254-0500 E QUERY    [js] SyntaxError: missing ) in parenthetical @(shell):1:71
  </code></pre>
  
  <p>I tried replacing the expression "postal code" with something else that doesn't take a space, and it works fine.</p>