title: coffeescript check if not in array
body: <p>Here's something simple to check if user is in moderator. But I want to check if user is not in moderator.</p>
  
  <pre><code>if err &amp;&amp; user in moderators
    return
  </code></pre>
  
  <p>Intuitively it would be like this</p>
  
  <pre><code>if err &amp;&amp; user isnt in moderators
    return
  </code></pre>
  
  <p>But obviously this doesn't work. What's the best way to do it?</p>