title: underscore js, isFunction
body: <p>In underscorejs</p>
  
  <pre><code>if (typeof /./ != 'function' &amp;&amp; typeof Int8Array != 'object' &amp;&amp; typeof nodelist != 'function') {
      _.isFunction = function(obj) {
        return typeof obj == 'function' || false;
      };
    }
  </code></pre>
  
  <p>why it is not only <code>return typeof obj == 'function';</code>?</p>
  
  <p>what that <code>|| false</code> give us?</p>