import { PropertyGroupDescription } from '../models/GroupDescription';
import { SortDescription } from '../models/SortDescription';
import { CollectionViewGroup } from './CollectionViewGroup';
export interface GroupResult<T> {
    groups: CollectionViewGroup<T>[];
    /** Leaves reordered so items of the same group are contiguous. */
    leaves: T[];
}
/**
 * Build the group tree for `items` (already filtered and sorted) against the
 * given descriptions. Groups within a level are ordered by their key, honoring
 * the sort direction of any {@link SortDescription} on that level's property
 * (so sorting a grouped column reverses its groups). Leaves keep the incoming
 * order. Returns the tree and the leaves reordered to match, so a caller can use
 * the reordered array as its view.
 */
export declare function buildGroups<T>(items: T[], descriptions: PropertyGroupDescription<T>[], sorts?: SortDescription[]): GroupResult<T>;