/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import { Provider } from '../../di';
import { ChangeDetectorRef } from '../change_detector_ref';
/**
 * A strategy for tracking changes over time to an iterable. Used for {@link NgFor} to
 * respond to changes in an iterable by effecting equivalent changes in the DOM.
 *
 * @stable
 */
export interface IterableDiffer {
    diff(object: any): any;
    onDestroy(): any;
}
/**
 * An optional function passed into {@link NgFor} that defines how to track
 * items in an iterable (e.g. by index or id)
 *
 * @stable
 */
export interface TrackByFn {
    (index: number, item: any): any;
}
/**
 * Provides a factory for {@link IterableDiffer}.
 *
 * @stable
 */
export interface IterableDifferFactory {
    supports(objects: any): boolean;
    create(cdRef: ChangeDetectorRef, trackByFn?: TrackByFn): IterableDiffer;
}
/**
 * A repository of different iterable diffing strategies used by NgFor, NgClass, and others.
 * @stable
 */
export declare class IterableDiffers {
    factories: IterableDifferFactory[];
    constructor(factories: IterableDifferFactory[]);
    static create(factories: IterableDifferFactory[], parent?: IterableDiffers): IterableDiffers;
    /**
     * Takes an array of {@link IterableDifferFactory} and returns a provider used to extend the
     * inherited {@link IterableDiffers} instance with the provided factories and return a new
     * {@link IterableDiffers} instance.
     *
     * The following example shows how to extend an existing list of factories,
           * which will only be applied to the injector for this component and its children.
           * This step is all that's required to make a new {@link IterableDiffer} available.
     *
     * ### Example
     *
     * ```
     * @Component({
     *   viewProviders: [
     *     IterableDiffers.extend([new ImmutableListDiffer()])
     *   ]
     * })
     * ```
     */
    static extend(factories: IterableDifferFactory[]): Provider;
    find(iterable: any): IterableDifferFactory;
}
