/**
 * Triggers a callback when the Escape key is pressed.
 *
 * @remarks
 * This hook subscribes to the global `keyup$` observable and filters for the "Escape" key.
 * Useful for closing modals, tooltips, or cancelling actions.
 *
 * @param fn - The function to call when Escape is pressed.
 *
 * @example
 * ```tsx
 * useOnEscape(() => {
 *   setIsOpen(false);
 * });
 * ```
 */
export declare function useOnEscape(fn: (e: KeyboardEvent) => void): void;