import type { Ref } from "vue";
declare const defaultThreshold: readonly [0, 0.3, 0.5, 0.8, 1];
/**
 * 观察 document.body 下子元素的可见性.
 */
export declare const elementVisibility: {
    watch: (element: Element, threshold: (typeof defaultThreshold)[number]) => Ref<boolean>;
    unwatch: (element: Element) => void;
    unwatchAll: () => void;
    destroy: () => void;
};
/**
 * 指定根元素并观察根元素下子元素的可见性
 * @param root 根元素
 * @param options 选项
 */
export declare function elementVisibilityWithRoot(root: Element, options?: IntersectionObserverInit): {
    watch: (element: Element, threshold: (typeof defaultThreshold)[number]) => Ref<boolean>;
    unwatch: (element: Element) => void;
    unwatchAll: () => void;
    destroy: () => void;
};
export {};