/**
 * Tracks previous state of a value.
 *
 * @param value Props, state or any other calculated value.
 * @returns Value from the previous render of the enclosing component.
 *
 * @example
 * function Component() {
 *   const [count, setCount] = useState(0);
 *   const prevCount = usePrevious(count);
 *   // ...
 *   return `Now: ${count}, before: ${prevCount}`;
 * }
 */
export default function usePrevious<T>(value: T): T | undefined;