import { Observable } from 'rxjs';
import { Group } from '../IGroupChangeSet';
import { ChangeSetOperatorFunction } from '../ChangeSetOperatorFunction';
/**
 *  Groups the source on the value returned by group selector factory.
 * @typeparam TObject The type of the object.
 * @typeparam TKey The type of the key.
 * @typeparam TGroupKey The type of the group key.
 * @param groupSelectorKey The group selector key.
 * @param regrouper Invoke to  the for the grouping to be re-evaluated
 */
export declare function groupOn<TObject, TKey, TGroupKey>(groupSelectorKey: (value: TObject) => TGroupKey, regrouper?: Observable<unknown>): ChangeSetOperatorFunction<TObject, TKey, Group<TObject, TKey, TGroupKey>, TGroupKey>;