import { GroupRow } from './types';
import { ObjectForExtending } from '../types';

export declare function objectGroupBy<T extends ObjectForExtending>(items: T[], keyGetter: (item: T) => string): Record<string, T[]>;
export declare function groupsToArr<T, V extends ObjectForExtending, X>(groups: Record<string, readonly T[]>, groupRowReplaceTo: ((groupRow: GroupRow<X>) => X | GroupRow<X>) | undefined, options?: {
    labelKey?: string;
    itemsKey?: string;
    additionalPropertiesForGroup?: (groupLabel: string, items: readonly T[]) => V;
}): (X | GroupRow<X> | {
    [x: string]: any;
})[];
export declare function rowGrouper<Row extends ObjectForExtending>(rows: readonly Row[], columnKey: string): Record<string, readonly Row[]>;