/**
 * Returns a ref to attach to a container. While `active` is `true`:
 *   - Initial focus moves to the first focusable child (or the container itself
 *     if it has `tabindex`).
 *   - Tab and Shift+Tab cycle within the container.
 *   - On deactivate, focus is restored to whatever was focused before.
 *
 * @param active - Whether the trap is engaged.
 * @returns A ref callback to attach to the container element.
 *
 * @example
 * const trapRef = useFocusTrap<HTMLDivElement>(open);
 * <div ref={trapRef}>…</div>
 */
export declare function useFocusTrap<T extends HTMLElement = HTMLElement>(active: boolean): (node: T | null) => void;