React Base Fiddle (JSX)

Starting point for creating JSFiddles with React. This uses React with Addons.

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.24/browser.js"></script>
<script src="https://fb.me/react-with-addons-15.0.1.js"></script>
<script src="https://fb.me/react-dom-15.0.1.js"></script>
<script src="https://facebook.github.io/react/js/jsfiddle-integration-babel.js"></script>

<div id="container">
    <!-- This element's contents will be replaced with your component. -->
</div>

JavaScript 1.7

var Child = React.createClass({
  render() {
    return <input ref={ node => 
      node && this.props.shouldFocus && node.focus()
    } />
  }
})

var Parent = React.createClass({
	getInitialState() {
    return { shouldFocus: false }
  },

	toggleFocus(node) {
    this.setState({ shouldFocus: !this.state.shouldFocus })
  },

  render: function() {
    return (
      <div>
      	<button onClick={() => this.toggleFocus() }>focus</button>
        <Child shouldFocus={this.state.shouldFocus} />
      </div>
    )
  }
});

ReactDOM.render(
  <Parent />,
  document.getElementById('container')
);