/**
* Track whether a component is current mounted. Generally less preferable than
* properlly canceling effects so they don't run after a component is unmounted,
* but helpful in cases where that isn't feasible, such as a `Promise` resolution.
*
* @returns a function that returns the current isMounted state of the component
*
* ```ts
* const [data, setData] = useState(null)
* const isMounted = useMounted()
*
* useEffect(() => {
* fetchdata().then((newData) => {
* if (isMounted()) {
* setData(newData);
* }
* })
* })
* ```
*/
export default function useMounted(): () => boolean;