import React from 'react';

const App = React.createClass({
  render: function() {
    return (
      <h1>Hello React :)</h1>
    );
  }
});
export default App;

import React, {Component} from 'react';

class App extends Component {
  render() {
    return (
      <h1>Hello React :)</h1>
    );
  }
}
export default App;

Switch back to class based component definition.
Switch back to class based component definition.

Our tutorial asks students to go from this to createClass