import type { IStream } from '../types.js';
/**
 * Accumulate values from a stream
 *
 * stream:       -1-2-3->
 * reduce(+, 0): 01-3-6->
 */
export declare const reduce: IReduceCurry;
export type ReduceFunction<I, O> = (acc: O, value: I) => O;
export interface IReduceCurry {
    <I, O>(f: ReduceFunction<I, O>, initial: O, s: IStream<I>): IStream<O>;
    <I, O>(f: ReduceFunction<I, O>, initial: O): (s: IStream<I>) => IStream<O>;
    <I, O>(f: ReduceFunction<I, O>): (initial: O) => (s: IStream<I>) => IStream<O>;
}