// Create a theme context, defaulting to light theme const ThemeContext = React.createContext('light'); // Signed-in user context const UserContext = React.createContext(); class App extends React.Component { static propTypes = { theme: PropTypes.string, signedInUser: PropTypes.shape({ id: number, name: string, avatar: string, }), }; render() { return ( {theme => ( {user => ( )} )} ); } }