import { DisposeCallback, ObservableLike, Observer, Subscription } from './types';
export declare const PENDING: never;
export default class Observable<T> implements ObservableLike<T> {
    constructor(factory: (observer: Observer<T>) => DisposeCallback | undefined | void);
    private factory;
    private teardown;
    private observers;
    private hasCompleted;
    protected currentValue: T | (typeof PENDING);
    subscribe(subscriber: Observer<T> | Observer<T>['next']): Subscription;
    static of<T>(value: T): ObservableLike<T>;
    static from<T>(values: Array<T>): ObservableLike<T>;
    static empty(): ObservableLike<never>;
    static never(): ObservableLike<never>;
    static defer<T>(observableFactory: () => ObservableLike<T>): ObservableLike<T>;
}