title: Explanation for: "function" == typeof code?
body: <p>I am working on someone script and I don't understand following line. Can someone explain me this line?</p>
  
  <pre><code> var self = this,
   "function" == typeof self.options.callback &amp;&amp; self.options.callback.call(self)
   callback: function() { .. }
  </code></pre>
  
  <p><strong>options is object</strong></p>