import { ElementRef, ChangeDetectorRef, OnDestroy, AfterViewInit } from '@angular/core';
export declare class VirtualHelperBaseDirective implements OnDestroy, AfterViewInit {
    elementRef: ElementRef;
    cdr: ChangeDetectorRef;
    scrollAmount: number;
    _size: number;
    destroyed: any;
    private _afterViewInit;
    private _scrollNativeSize;
    ngAfterViewInit(): void;
    onScroll(event: any): void;
    constructor(elementRef: ElementRef, cdr: ChangeDetectorRef);
    get nativeElement(): any;
    ngOnDestroy(): void;
    set size(value: number);
    get size(): number;
    get scrollNativeSize(): number;
    calculateScrollNativeSize(): number;
}
