/**
 * @fileoverview IntersectionObserver hook for viewport visibility detection.
 * @author Saasflare™
 * @module packages/ui/hooks/use-intersection-observer
 * @package ui
 *
 * @example
 * const ref = useRef<HTMLDivElement>(null);
 * const entry = useIntersectionObserver(ref, { threshold: 0.5 });
 * const isVisible = entry?.isIntersecting ?? false;
 */
import { type RefObject } from 'react';
/** Options for the IntersectionObserver */
export interface UseIntersectionObserverOptions {
    /** Margin around the root. Default: `'0px'` */
    rootMargin?: string;
    /** Visibility threshold(s) between 0 and 1. Default: `0` */
    threshold?: number | number[];
    /** Root element for intersection (defaults to viewport) */
    root?: Element | null;
    /** Only trigger once then disconnect. Default: `false` */
    triggerOnce?: boolean;
    /** Whether the observer is active. Default: `true` */
    enabled?: boolean;
}
/**
 * Observes an element's intersection with the viewport or a root element.
 * Returns the latest IntersectionObserverEntry.
 *
 * @param {RefObject<Element | null>} ref - The element to observe
 * @param {UseIntersectionObserverOptions} [options] - Observer configuration
 * @returns {IntersectionObserverEntry | null} The latest intersection entry
 *
 * @example
 * const sectionRef = useRef<HTMLElement>(null);
 * const entry = useIntersectionObserver(sectionRef, {
 *   threshold: [0, 0.25, 0.5, 0.75, 1],
 *   rootMargin: '-100px',
 * });
 * const ratio = entry?.intersectionRatio ?? 0;
 */
export declare function useIntersectionObserver(ref: RefObject<Element | null>, options?: UseIntersectionObserverOptions): IntersectionObserverEntry | null;