import * as i0 from "@angular/core";
export interface ScrollSpyTarget {
    onScrollY(y: number): void;
}
export declare class ScrollSpyService {
    private platformId;
    private items;
    private ticking;
    private bound;
    constructor(platformId: object);
    register(item: ScrollSpyTarget): void;
    unregister(item: ScrollSpyTarget): void;
    private onScroll;
    private rafTick;
    static ɵfac: i0.ɵɵFactoryDeclaration<ScrollSpyService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<ScrollSpyService>;
}