import { ElGetters, ElTreeGridPresentationNode } from './tree-grid.model';
export declare class ElTreeGridDataService<T> {
    private defaultGetters;
    toPresentationNodes<N>(nodes: N[], customGetters?: ElGetters<N, T>, level?: number): ElTreeGridPresentationNode<T>[];
    private mapNodes;
    flattenExpanded(nodes: ElTreeGridPresentationNode<T>[]): ElTreeGridPresentationNode<T>[];
    copy(nodes: ElTreeGridPresentationNode<T>[]): ElTreeGridPresentationNode<T>[];
}