import { Any, AnyObject, Options, SortSpec } from "../../types";
interface InputExpr {
    n: number;
    sortBy: SortSpec;
    output: Any;
}
/**
 * Returns an aggregation of the top n elements within a group, according to the specified sort order.
 * If the group contains fewer than n elements, $topN returns all elements in the group.
 */
export declare const $topN: (coll: AnyObject[], expr: InputExpr, options: Options) => unknown[];
export {};