title: React: Cleanest way of accessing component without using "this"
body: <p>I need to access a React component within a function nested within a a handler function. </p>
  
  <p>When in a nested function <code>this</code> does not give a reference to the component</p>
  
  <p>so I explicitly declare it instead of doing the usual <code>this.setState(...)</code></p>
  
  <p>Is there a cleaner way to do this than my following code?</p>
  
  <pre><code>React.createClass({
  
      uploadImage : function() {
      ...
      var componentReference = this
  
      xhrRequest.onreadystatechange = function()
          {if(request.readyState==4) {
          componentReference.setState({uploadStatus: request.status});
          }
      }
  </code></pre>