import { IObservable } from '../internal/Observable';
export declare type TReducer<T, R> = (memory: R, current: T) => R;
export declare type TSeed<R> = R;
export declare type TSource<T> = IObservable<T>;
export declare type TResult<R> = IObservable<R>;
export declare const scan: {
    <T, R>(reducer: TReducer<T, R>, seed: R, source: IObservable<T>): IObservable<R>;
    <T, R>(reducer: TReducer<T, R>): (seed: R, source: IObservable<T>) => IObservable<R>;
    <T, R>(reducer: TReducer<T, R>, seed: R): (source: IObservable<T>) => IObservable<R>;
    <T, R>(reducer: TReducer<T, R>): (seed: R) => (source: IObservable<T>) => IObservable<R>;
};