title: Why are helper methods frequently used in Javascript?
body: <p>New to Javascript, reading Crockford's Javascript: The Good Parts (among other things)</p>
  
  <p>In the 4th chapter regarding functions Crockford is showing how to preserve this in the outer function for use in inner functions, which I understand.</p>
  
  <p>My question is, in his example code and a ton more like it, why use this helper function:</p>
  
  <pre><code>myObject.double = function() {
    var that = this; 
  
    var helper = function () {
        that.value = add(that.value, that.value);
    }
    helper();
  };
  </code></pre>
  
  <p>Is it maybe because add() is sitting out in global scope, while value is in myObject, so I need to copy this (myObject) then transfer to global where I can grab add()?</p>
  
  <p>Otherwise I'm not sure why I need the helper function?</p>