import { AbortablePromise } from './AbortablePromise';
/**
 * Publish–subscribe pattern implementation that guarantees the delivery of published messages even if any of listeners
 * would throw an error.
 *
 * @template T The published message.
 */
export declare class PubSub<T = void> {
    private _listeners;
    /**
     * The number of subscribed listeners.
     */
    get listenerCount(): number;
    /**
     * Synchronously invokes listeners with the published message.
     *
     * @param message The published message.
     */
    publish(message: T): void;
    /**
     * Waits for a message that satisfies the given predicate to be published and resolves with that message.
     *
     * @template R A subtype of T that the predicate function identifies as satisfying the condition.
     * @param predicate A function that takes the message as a parameter and returns true if the message satisfies the condition, otherwise false.
     * @returns An {@link AbortablePromise} that resolves with the published message that satisfies the predicate.
     */
    waitFor<R extends T>(predicate: (message: T) => message is R): AbortablePromise<R>;
    /**
     * Waits for a message that satisfies the given predicate to be published and resolves with that message.
     *
     * @param predicate A function that takes the message as a parameter and returns true if the message satisfies the condition, otherwise false.
     * @returns An {@link AbortablePromise} that resolves with the published message that satisfies the predicate.
     */
    waitFor(predicate: (message: T) => boolean): AbortablePromise<T>;
    /**
     * Adds a listener that would receive all messages published via {@link publish}.
     *
     * @param listener The callback.
     * @returns The callback that unsubscribes the listener.
     */
    subscribe(listener: (message: T) => any): () => void;
    /**
     * Unsubscribes a listener.
     *
     * @param listener The callback that was previously {@link subscribe subscribed}.
     */
    unsubscribe(listener: (message: T) => any): void;
    /**
     * Unsubscribes all listeners.
     */
    unsubscribeAll(): void;
}