js
class Layout extends Component {
  state = { isSidebarExpanded: true };

  handleRouteChange = (url) => this.setState({ isSidebarExpanded: true });

  componentDidMount() {
    Router.events.on('routeChangeComplete', handleRouteChange);
    this.beforeUnmounting(() -> Router.events.off('routeChangeComplete', this.handleRouteChange));
  }
  // ...