title: React JS Cannot read property 'keys' of undefined
body: <p>I am beginning to learn React through a tutorial, however I ran into this error when I ran the code that I created. </p>
  
  <p>The error seems to be one that has to do with the framework of the languages. Perhaps with the version of Babel that I imported for the translation.</p>
  
  <p>Does anyone know the actual situation and how to find a soulution.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  
  &lt;html&gt;
  &lt;head&gt;
      &lt;meta name="viewport" content="width=device-width" /&gt;
      &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.0.1/react.min.js"&gt;&lt;/script&gt;
      &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.0.1/react-dom.min.js"&gt;&lt;/script&gt;
      &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/6.1.19/browser.js"&gt;&lt;/script&gt;
      &lt;title&gt;ReactJs&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;script type="text/babel"&gt;
          var HelloWorld = ReactDOM.createClass({
          render: function() {
          return &lt;div&gt;
          &lt;h1&gt;Hello World&lt;/h1&gt;
          &lt;p&gt;This is some text&gt;&lt;/p&gt;
          &lt;/div&gt;
          }
          });
          ReactDOM.render(&lt;HelloWorld/&gt;, document.body);
      &lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>