import { AccumulatorOperator } from "../../types";
/**
 * Returns the top element within a group according to the specified sort order.
 *
 * @param {Any[]} collection The input array
 * @param {AnyObject} expr The right-hand side expression value of the operator
 * @param {Options} options The options to use for this operation
 * @returns {*}
 */
export declare const $top: AccumulatorOperator;