import { RefObject } from 'react';
/**
 * Tracks whether the referenced element or any of its descendants have focus.
 * Similar to the :focus-within CSS pseudo-class.
 *
 * @param elementRef The React ref attached to the container element.
 * @returns `true` if the element or a descendant has focus, `false` otherwise.
 */
export declare function useFocusWithinState(elementRef: RefObject<HTMLElement>): boolean;