import { AfterContentInit, ElementRef, EventEmitter, OnChanges, OnDestroy, OnInit, SimpleChanges } from '@angular/core';
import * as i0 from "@angular/core";
export declare class InfiniteScrollDirective<T = unknown> implements OnInit, AfterContentInit, OnChanges, OnDestroy {
    private readonly _element;
    load: InfiniteScrollLoadFunction<T>;
    _collection: T[];
    get collection(): T[];
    set collection(value: T[]);
    set scrollElement(element: ElementRef | HTMLElement);
    enabled: boolean;
    filter: any;
    loadOnInit: boolean;
    loadOnScroll: boolean;
    pageSize: number;
    collectionChange: EventEmitter<T[]>;
    loadingEvent: EventEmitter<InfiniteScrollLoadingEvent<any>>;
    loadedEvent: EventEmitter<InfiniteScrollLoadedEvent<any, any>>;
    loadErrorEvent: EventEmitter<InfiniteScrollLoadErrorEvent<any>>;
    private readonly _loadButtonQuery;
    private readonly _loadingIndicatorQuery;
    private _pages;
    private _nextPageNum;
    private _domObserver;
    private _scrollEventSub;
    private readonly _updateRequests;
    private readonly _isLoading;
    private readonly _isExhausted;
    private readonly _loadButtonEnabled;
    private readonly _canLoadManually;
    private _scrollElement;
    private _subscriptions;
    private _loadButtonSubscriptions;
    private readonly _onDestroy;
    constructor();
    ngOnInit(): void;
    ngAfterContentInit(): void;
    ngOnChanges(changes: SimpleChanges): void;
    ngOnDestroy(): void;
    /**
     * Request an additional page of data.
     */
    loadNextPage(): void;
    /**
     * Request a check for whether an additional page of data is required. This is throttled.
     */
    check(): void;
    /**
     * Clear the collection. Future requests will load from page 0.
     */
    reset(clearSubscriptions?: boolean): void;
    /**
     * Reload the data without clearing the view.
     */
    reload(): void;
    /**
     * Reload the data in a specific page without clearing the view.
     * @param pageNum Page number
     */
    reloadPage(pageNum: number): void;
    /** A filter value of null or undefined should be considered the same as an empty string */
    private coerceFilter;
    /**
     * Attach scroll event handler and DOM observer.
     */
    private attachEventHandlers;
    /**
     * Detach scroll event handler and DOM observer.
     */
    private detachEventHandlers;
    /**
     * Remove any existing event subscriptions for the load button `loading` event, then attach
     * subscriptions
     * for any in the query.
     */
    private attachLoadButtonEvents;
    /**
     * Conditionally loads a page into the collection based on directive state and request parameters.
     */
    private doRequest;
    /**
     * Returns true if the request should be fulfilled.
     */
    private needsData;
    /**
     * Updates state for the beginning of a load. Returns false if the `loading` event was cancelled.
     */
    private beginLoading;
    private setPageItems;
    /**
     * Updates state from a successful load. Raises the `loaded` event.
     */
    private endLoading;
    /**
     * Updates state from a failed load. Raises the `loadError` event.
     */
    private endLoadingWithError;
    static ɵfac: i0.ɵɵFactoryDeclaration<InfiniteScrollDirective<any>, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<InfiniteScrollDirective<any>, "[uxInfiniteScroll]", ["uxInfiniteScroll"], { "load": { "alias": "uxInfiniteScroll"; "required": false; }; "_collection": { "alias": "collection"; "required": false; }; "scrollElement": { "alias": "scrollElement"; "required": false; }; "enabled": { "alias": "enabled"; "required": false; }; "filter": { "alias": "filter"; "required": false; }; "loadOnInit": { "alias": "loadOnInit"; "required": false; }; "loadOnScroll": { "alias": "loadOnScroll"; "required": false; }; "pageSize": { "alias": "pageSize"; "required": false; }; }, { "collectionChange": "collectionChange"; "loadingEvent": "loading"; "loadedEvent": "loaded"; "loadErrorEvent": "loadError"; }, ["_loadButtonQuery", "_loadingIndicatorQuery"], never, false, never>;
}
export type InfiniteScrollLoadFunction<T = any, S = any> = (pageNum: number, pageSize: number, filter: S) => T[] | Promise<T[]>;
/**
 * Event raised before the `loading` function is called.
 */
export declare class InfiniteScrollLoadingEvent<S = any> {
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number;
    /**
     * The number of items requested.
     */
    pageSize: number;
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S;
    private _defaultPrevented;
    constructor(
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number, 
    /**
     * The number of items requested.
     */
    pageSize: number, 
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S);
    /**
     * Prevents the default behaviour of the `loading` event (loading function will not be called).
     */
    preventDefault(): void;
    defaultPrevented(): boolean;
}
/**
 * Event raised when the loading function result has been resolved and added to the collection.
 */
export declare class InfiniteScrollLoadedEvent<T = any, S = any> {
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number;
    /**
     * The number of items requested.
     */
    pageSize: number;
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S;
    /**
     * The result of the promise returned from the loading function.
     */
    data: T[];
    /**
     * True if the data is considered exhausted (number of items returned less than `pageSize`).
     */
    exhausted: boolean;
    constructor(
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number, 
    /**
     * The number of items requested.
     */
    pageSize: number, 
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S, 
    /**
     * The result of the promise returned from the loading function.
     */
    data: T[], 
    /**
     * True if the data is considered exhausted (number of items returned less than `pageSize`).
     */
    exhausted: boolean);
}
/**
 * Event raised if the loading function returns a rejected promise.
 */
export declare class InfiniteScrollLoadErrorEvent<S = any> {
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number;
    /**
     * The number of items requested.
     */
    pageSize: number;
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S;
    /**
     * The object provided when rejecting the promise.
     */
    error: any;
    constructor(
    /**
     * The index of the requested page, starting from 0.
     */
    pageNumber: number, 
    /**
     * The number of items requested.
     */
    pageSize: number, 
    /**
     * The filter details as provided via the `filter` binding.
     */
    filter: S, 
    /**
     * The object provided when rejecting the promise.
     */
    error: any);
}