import { Downstream, Upstream } from 'callbag-state';
import { KeyedChangeStream } from './types';
import { Watcher } from './watcher';
export declare function keyDownstream<T>(src: KeyedChangeStream<T>, key: string | number, watcher: Watcher<T>, current: () => T | undefined): Downstream<T>;
export declare function keyUpstream<T>(src: Upstream<T[]>, key: string | number, watcher: Watcher<T>, ref: () => T[]): Upstream<T>;