import { ElementRef, OnDestroy } from '@angular/core';
import { Observable } from 'rxjs';
import { KitPlatformService } from '../kit-platform/kit-platform.service';
/**
 * Observe viewport intersection.
 *
 * Should be provided on a component or a directive.
 *
 *
 * ### Usage
 *
 * Provide `KitIntersectionService` on a component or a directive, that you want to observe.
 *
 * ```typescript
 * \@Component({
 *   ...
 *   providers: [
 *     KitIntersectionService,
 *   ],
 * })
 * export class TestComponent {
 *   constructor(private intersection: KitIntersectionService) {
 *   }
 *   ...
 *   // Check
 *   const visible = this.instersection.isIntersecting;
 *   ...
 *   // Observe
 *   this.instersection.observe().subscribe(isIntersecting => {
 *   });
 * }
 * ```
 */
export declare class KitIntersectionService implements OnDestroy {
    private elementRef;
    private platform;
    private observer;
    private io;
    constructor(elementRef: ElementRef, platform: KitPlatformService);
    readonly isIntersecting: boolean;
    ngOnDestroy(): void;
    observe(): Observable<boolean | null>;
    private initObserver;
}