import { AsyncSequence } from "../../sequency";
export declare class MaxBy {
    /**
     * Returns the maximum element by comparing the results of the given `selector` function
     * for each element of the sequence or `null` if the sequence is empty.
     *
     * @param {(value: T) => Promise<R> | R} selector
     * @returns {Promise<T | null>}
     */
    maxBy<T, R>(this: AsyncSequence<T>, selector: (value: T) => Promise<R> | R): Promise<T | null>;
}