import type { Cleanup, SignalOptions } from './types.ts';
interface VisibilityOptions extends SignalOptions {
    threshold?: number | number[];
    root?: Element | null;
    rootMargin?: string;
    once?: boolean;
}
interface ResizeOptions extends SignalOptions {
    box?: ResizeObserverBoxOptions;
}
/**
 * Observes an element's visibility via IntersectionObserver.
 *
 * Returns a cleanup function that disconnects the observer.
 *
 * @example
 *
 *     const stop = watchVisibility(img, (entry) => {
 *
 *         if (entry.isIntersecting) loadImage(img);
 *     }, { threshold: 0.5, once: true });
 */
export declare function watchVisibility(el: Element, cb: (entry: IntersectionObserverEntry) => void, opts?: VisibilityOptions): Cleanup;
/**
 * Observes an element's size via ResizeObserver.
 *
 * Returns a cleanup function that disconnects the observer.
 *
 * @example
 *
 *     const stop = watchResize(panel, (entry) => {
 *
 *         const { width } = entry.contentRect;
 *         if (width < 400) compact(panel);
 *     });
 */
export declare function watchResize(el: Element, cb: (entry: ResizeObserverEntry) => void, opts?: ResizeOptions): Cleanup;
export {};