cookies.jsx

Cookies = React.createClass({
  render() {
    return (
      <div className="cookie">
        <h3>I'd like to eat a <span style={{color: 'orange'}}>{this.props.cookie}</span> cookie.</h3>
      </div>
    );
  }
});

layout.jsx

App = React.createClass({
  render() {
    return (
      <div class="app-root">
        <div class="container">
          <Cookies />
        </div>
      </div>
    );
  }
});

router.js

FlowRouter.route( '/cookies/:cookie', {
  name: 'cookies',
  action( params ) {
    ReactLayout.render( App, { yield: <Cookies cookie={params.cookie} /> } );
  }
});