Page.jsx

import HomePage from './HomePage.jsx';
import AboutPage from './AboutPage.jsx';
import UserPage from './UserPage.jsx';
import FourOhFourPage from './FourOhFourPage.jsx';

const PAGES = {
  home: HomePage,
  about: AboutPage,
  user: UserPage,
};

const Page = (props) => {
  const Handler = PAGES[props.page] || FourOhFourPage;
  
  return <Handler {...props} />
};

Page.propTypes = {
    page: PropTypes.oneOf(Object.keys(PAGES)).isRequired,
};