React useTitle hook
Sets the title of the page
- Use typeofto determine if theDocumentis defined or not.
- Use the useRef()hook to store the original title of theDocument, if defined.
- Use the useEffect()hook to setDocument.titleto the passed value when the component mounts and clean up when unmounting.
const useTitle = title => {
  const documentDefined = typeof document !== 'undefined';
  const originalTitle = React.useRef(documentDefined ? document.title : null);
  React.useEffect(() => {
    if (!documentDefined) return;
    if (document.title !== title) document.title = title;
    return () => {
      document.title = originalTitle.current;
    };
  }, []);
};
const Alert = () => {
  useTitle('Alert');
  return <p>Alert! Title has changed</p>;
};
const MyApp = () => {
  const [alertOpen, setAlertOpen] = React.useState(false);
  return (
    <>
      <button onClick={() => setAlertOpen(!alertOpen)}>Toggle alert</button>
      {alertOpen && <Alert />}
    </>
  );
};
ReactDOM.render(<MyApp />, document.getElementById('root'));