hooks.js

const App = () => {
  const [value, setValue] = useState(// ...get initial value here
  const onChange = event => setValue(event.target.value);
  
  useEffect(// ...update localStorage here
  
  return (
    <div>
      <input value={value} type='text' onChange={onChange} />
      <p>{value}</p>
    </div>
  );
};