import { Sequence } from "../../sequency";
export declare class ReduceIndexed {
    /**
     * Reduces the whole sequence to a single value by invoking `operation` with each element
     * from left to right. For every invocation of the operation `acc` is the result of the last
     * invocation. For the first invocation of the operation `acc` is the first element of the
     * sequence. In addition the `index` of the current element is also passed to the operation.
     *
     * @param {(index: number, acc: S, element: T) => S} operation
     * @returns {S}
     */
    reduceIndexed<S, T extends S>(this: Sequence<T>, operation: (index: number, acc: S, element: T) => S): S;
}