import { type MaybePromise } from '@augment-vir/common';
import { type PartInfo } from '../../lit-exports/all-lit-exports.js';
/**
 * Callback called by the {@link onIntersect} directive.
 *
 * @category Internal
 */
export type OnIntersectCallback = (params: {
    entry: IntersectionObserverEntry;
    allEntries: IntersectionObserverEntry[];
    observer: IntersectionObserver;
    element: Element;
}) => MaybePromise<void>;
/**
 * Options used for the {@link onIntersect} directive.
 *
 * @category Internal
 */
export type OnIntersectOptions = IntersectionObserverInit;
/**
 * A directive that fires its listener any time the element's configured "intersection" is crossed.
 * This is commonly use for detecting when an element has scrolled into view. This uses the
 * [built-in `IntersectionObserver`
 * API](https://developer.mozilla.org/docs/Web/API/IntersectionObserver/IntersectionObserver), so it
 * is very efficient.
 *
 * @category Directives
 * @example
 *
 * ```ts
 * import {html, defineElement, onIntersect} from 'element-vir';
 *
 * const MyElement = defineElement()({
 *     tagName: 'my-element',
 *     render() {
 *         return html`
 *             <div
 *                 ${onIntersect({threshold: 1}, ({element, entry}) => {
 *                     if (entry.isIntersecting) {
 *                         console.log('is intersecting!');
 *                     } else {
 *                         console.log('is not intersecting');
 *                     }
 *                 })}
 *             >
 *                 Some div
 *             </div>
 *         `;
 *     },
 * });
 * ```
 */
export declare const onIntersect: (options: IntersectionObserverInit, callback: OnIntersectCallback) => import("lit-html/directive.js").DirectiveResult<{
    new (partInfo: PartInfo): {
        element: Element | undefined;
        options: OnIntersectOptions | undefined;
        intersectionObserver: undefined | IntersectionObserver;
        callback: OnIntersectCallback | undefined;
        fireCallback(entries: IntersectionObserverEntry[], observer: IntersectionObserver): void;
        update(partInfo: PartInfo, [options, callback,]: [OnIntersectOptions, OnIntersectCallback]): undefined;
        render(options: OnIntersectOptions, callback: OnIntersectCallback): undefined;
        readonly _$isConnected: boolean;
    };
}>;