import { AfterViewInit, ElementRef, EventEmitter, OnDestroy } from '@angular/core';
import * as i0 from "@angular/core";
export declare class NgIsInViewDirective implements AfterViewInit, OnDestroy {
    private _elementRef;
    emitViewEventOnce: boolean;
    onIsVisibleChanged: EventEmitter<boolean>;
    private _observer?;
    constructor(_elementRef: ElementRef);
    ngAfterViewInit(): void;
    ngOnDestroy(): void;
    private disconnectObserver;
    static ɵfac: i0.ɵɵFactoryDeclaration<NgIsInViewDirective, [{ host: true; }]>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<NgIsInViewDirective, "[ngIsInView]", never, { "emitViewEventOnce": { "alias": "emitViewEventOnce"; "required": false; }; }, { "onIsVisibleChanged": "onIsVisibleChanged"; }, never, never, true, never>;
}