React `useMemo` vs `useCallback`

const memoizedValue = useMemo(() => compute(a, b), [a, b]);

const memoizedCallback = useCallback(() => {
  doSomething(a, b);
}, [a, b]);

`useMemo` caches a calculated value, while `useCallback` caches a function definition. Use `useMemo` for expensive calculations and `useCallback` for passing callbacks to optimized child components.