import { GroupedObservable, Observable } from "rxjs";
export interface KeyChanges<K> {
    type: "add" | "remove";
    keys: Iterable<K>;
}
/**
 * Groups the elements from the source stream by using `keySelector`, returning
 * a stream of the active keys, and a function to get the stream of a specific group
 *
 * @param stream Input stream
 * @param keySelector Function that specifies the key for each element in `stream`
 * @param streamSelector Function to apply to each resulting group
 * @returns [1, 2]
 * 1. A function that accepts a key and returns the stream for the group of that key.
 * 2. A stream of KeyChanges, an object that describes what keys have been added or deleted.
 */
export declare function partitionByKey<T, K, R>(stream: Observable<T>, keySelector: (value: T) => K, streamSelector: (grouped: Observable<T>, key: K) => Observable<R>): [(key: K) => GroupedObservable<K, R>, Observable<KeyChanges<K>>];
/**
 * Groups the elements from the source stream by using `keySelector`, returning
 * a stream of the active keys, and a function to get the stream of a specific group
 *
 * @param stream Input stream
 * @param keySelector Function that specifies the key for each element in `stream`
 * @returns [1, 2]
 * 1. A function that accepts a key and returns the stream for the group of that key.
 * 2. A stream of KeyChanges, an object that describes what keys have been added or deleted.
 */
export declare function partitionByKey<T, K>(stream: Observable<T>, keySelector: (value: T) => K): [(key: K) => GroupedObservable<K, T>, Observable<KeyChanges<K>>];