import { OnInit, OnDestroy, ChangeDetectorRef } from '@angular/core';
import { ScrollSpyService } from './scroll-spy.service';
import * as i0 from "@angular/core";
/**
 * Spies on the spyTarget that has the provided `spyTargetId`.
 */
export declare class SpyDirective implements OnInit, OnDestroy {
    private scrollSpyService;
    private platformId;
    private changeDetectorRef;
    /**
     * ID of the spyTarget to spy.
     */
    spyTargetId: string;
    /**
     * @optional
     *
     * ID of the spyTargetContainer containing the spyTarget.
     */
    spyTargetContainerId?: string;
    /**
     * Class name to add to this element when the spyTarget has transitioned into a state of intersection (is visisble).
     *
     * @default
     * 'active'
     */
    spyActiveClass: string;
    activeClassInDOM?: string;
    private directiveDestroyed$;
    constructor(scrollSpyService: ScrollSpyService, platformId: string, changeDetectorRef: ChangeDetectorRef);
    ngOnInit(): void;
    ngOnDestroy(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<SpyDirective, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<SpyDirective, "[spy]", never, { "spyTargetId": "spyTargetId"; "spyTargetContainerId": "spyTargetContainerId"; "spyActiveClass": "spyActiveClass"; }, {}, never, never, true>;
}