basic-with-router.js

const MenuRenderer = React.createClass({
  contextTypes: {
    router: React.PropTypes.func.isRequired
  }
  
  componentWillReceiveProps(newProps, oldProps) {
    const router = this.context.router;
    console.log('new props', newProps, oldProps);
    // decide based on newProps or router
  }

  render() {
    const router = this.context.router;
    const menu = this.state.menu;
    // decide based on state or router
    return (<div>{ menu }</div>);
  }
});

render((
  <Router>
    <Route path="/" component={App}>
      <Route path="*" component={MenuRenderer} />
    </Route>
  </Router>
), document.body)