type Next<T> = (value: T) => void;
export type Observer<T> = {
    next(value: T): void;
    complete?(): void;
    error?(error: Error): void;
};
export type ObserverOrNext<T> = Next<T> | Observer<T>;
export declare function createObserver<T>(observerOrNext: ObserverOrNext<T>): Observer<T>;
export {};