var HelloComponent = React.createClass({
  render: function() {
    return (
      <div>
        <h1>Hello World</h1>
        <h2>My name is: {this.props.data}</h2>
      </div>
    );
  }
});

ReactDOM.render(
  <HelloComponent data={name: 'Matúš'} />,
  document.getElementById('app')
);