import { Subject } from 'rxjs';
import * as i0 from "@angular/core";
export declare class IsInViewportService implements IsInViewportServiceInterface {
    #private;
    private ngZone;
    observe(element: Element): Subject<IntersectionObserverEntry>;
    unobserve(element: Element): void;
    intersect(element: Element, entry: IntersectionObserverEntry): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<IsInViewportService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<IsInViewportService>;
}
export interface IsInViewportServiceInterface {
    observe(element: Element): Subject<IntersectionObserverEntry>;
    unobserve(element: Element): void;
    intersect(element: Element, entry: IntersectionObserverEntry): void;
}