import { LinkedListNode } from 'dbl-linked-list-ds';
export interface IObserver<T> {
    next(val: T): void;
    error(err: Error): void;
    complete(): void;
}
export declare class CompositeObserver<T> implements IObserver<T> {
    private observers;
    readonly length: number;
    add(observer: IObserver<T>): LinkedListNode<IObserver<T>>;
    remove(node: LinkedListNode<IObserver<T>>): void;
    next(val: T): void;
    error(err: Error): void;
    complete(): void;
}