import { PipeTransform } from "@angular/core";
import * as i0 from "@angular/core";
export declare class GroupByPipe implements PipeTransform {
    /**
     * Groups collection of items by property selector
     *
     * @param items Collection of items
     * @param key Property selector or property name
     * @returns Collection of grouped items, see {@link Group} for more details
     */
    transform<T, TKey extends keyof T>(items: T[], key: TKey): Group<T[TKey], T>[];
    transform<T, TKey>(items: T[], key: (item: T) => TKey): Group<TKey, T>[];
    static ɵfac: i0.ɵɵFactoryDeclaration<GroupByPipe, never>;
    static ɵpipe: i0.ɵɵPipeDeclaration<GroupByPipe, "groupBy", false>;
}