export { Observable as t };
type UnaryFunction<A, B> = (a: A) => B;
export interface ObservableLike<T> {
    subscribe(observerOrNext?: Observer<T> | ((value: T) => void)): Subscription;
}
/**
 * An `Observer` subscribes to an observable.
 */
export type Observer<T> = {
    next?(value: T): void;
    error?(error: unknown): void;
    complete?(): void;
};
/**
 * An `Operator` is a function that takes an observable as input and returns a
 * new observable as output.
 */
export type Operator<T, U> = (observable: ObservableLike<T>) => ObservableLike<U>;
/**
 * A `Subscription` is returned when an observer subscribes to an observable.
 */
export type Subscription = {
    unsubscribe(): void;
};
export declare enum State {
    Complete = "Complete",
    Error = "Error",
    NotComplete = "NotComplete",
    Unsubscribed = "Unsubscribed"
}
/**
 * Observables are lazy push data structures that can emit values both
 * synchronously and asynchronously. Observables are unicast and, unlike
 * promises, may never emit a value or may emit many values.
 *
 * @example
 *
 * ```
 * const observable = new Observable(observer => {
 *   observer.next(1);
 *   observer.next(2);
 *
 *   setTimeout(() => {
 *     observer.next(3);
 *     observer.complete();
 *   });
 * });
 *
 * // Logs the values 1 and 2 synchronously and then the value 3 asynchronously.
 * observable.subscribe(console.log);
 * ```
 *
 * @see https://reactivex.io/documentation/observable.html for an introduction
 * to observables.
 *
 * @see https://rxjs.dev for a more comprehensive observable library for
 * JavaScript.
 */
export declare class Observable<T> implements ObservableLike<T> {
    #private;
    constructor(subscribe: (observer: Observer<T>) => (() => void) | void);
    /**
     * Allows chaining operators to perform flow control.
     *
     * @example
     *
     * Observable.of(1, "2", 3, 4.5).pipe(
     *   filter(Number.isInteger),
     *   map(num => num * 2)
     * )
     */
    pipe(): Observable<T>;
    pipe<A>(op1: UnaryFunction<Observable<T>, A>): A;
    pipe<A, B>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>): B;
    pipe<A, B, C>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>): C;
    pipe<A, B, C, D>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>): D;
    pipe<A, B, C, D, E>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>): E;
    pipe<A, B, C, D, E, F>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>): F;
    pipe<A, B, C, D, E, F, G>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>, op7: UnaryFunction<F, G>): G;
    pipe<A, B, C, D, E, F, G, H>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>, op7: UnaryFunction<F, G>, op8: UnaryFunction<G, H>): H;
    pipe<A, B, C, D, E, F, G, H, I>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>, op7: UnaryFunction<F, G>, op8: UnaryFunction<G, H>, op9: UnaryFunction<H, I>): I;
    pipe<A, B, C, D, E, F, G, H, I>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>, op7: UnaryFunction<F, G>, op8: UnaryFunction<G, H>, op9: UnaryFunction<H, I>, ...operations: Operator<unknown, unknown>[]): Observable<unknown>;
    pipe<A, B, C, D, E, F, G, H, I>(op1: UnaryFunction<Observable<T>, A>, op2: UnaryFunction<A, B>, op3: UnaryFunction<B, C>, op4: UnaryFunction<C, D>, op5: UnaryFunction<D, E>, op6: UnaryFunction<E, F>, op7: UnaryFunction<F, G>, op8: UnaryFunction<G, H>, op9: UnaryFunction<H, I>, ...operations: Operator<unknown, unknown>[]): unknown;
    /**
     * Start receiving values from this observable as they are emitted.
     */
    subscribe(observerOrNext?: Observer<T> | ((value: T) => void)): Subscription;
}
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