import { ElementRef } from '@angular/core';
import * as i0 from "@angular/core";
export declare class NkSelectViewPortScrollDirective {
    private _element;
    viewPortScrollTarget: any;
    get scrollable(): boolean;
    private _clientHeight;
    private _scrollHeight;
    private _onSearchChangeSubscribe;
    constructor(_element: ElementRef);
    ngOnInit(): void;
    ngOnDestroy(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<NkSelectViewPortScrollDirective, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<NkSelectViewPortScrollDirective, "[view-port-scroll]", ["viewPortScroll"], { "viewPortScrollTarget": { "alias": "viewPortScrollTarget"; "required": false; }; }, {}, never, never, false, never>;
}