import { ElSortRequest } from '../tree-grid-sort.component';
import { ElTreeGridPresentationNode } from './tree-grid.model';
/**
 * Service used to sort tree grid data. Uses Array.prototype.sort method.
 * If you need custom sorting, you can extend this service and override comparator or whole sort method.
 */
export declare class ElTreeGridSortService<T> {
    sort(request: ElSortRequest, data: ElTreeGridPresentationNode<T>[]): ElTreeGridPresentationNode<T>[];
    protected comparator(request: ElSortRequest, na: ElTreeGridPresentationNode<T>, el: ElTreeGridPresentationNode<T>): number;
}