import { Observable } from "./observable";
/**
 * @category JDOM
 */
export type EventHandler = (...args: any[]) => void;
/**
 * Base interface for evented nodes in Jacdac
 * @category JDOM
 */
export interface IEventSource {
    readonly nodeId: number;
    changeId: number;
    /**
     * Subscribes to an event and returns the unsubscription handler
     * @param eventName
     * @param next
     */
    subscribe<T>(eventName: string | string[], next: (value: T) => void): () => void;
}
/**
 * Given a node or set of nodes, generate a stable string that can be used to track dependencies in frameworks like React.
 * @param nodes
 * @returns
 * @category JDOM
 */
export declare function dependencyId(nodes: IEventSource | IEventSource[]): string | number;
/**
 * Collects unsubscribe handlers and unmounts them
 */
export declare class JDCancellationToken {
    private subscriptions;
    constructor();
    mount(...items: (() => void)[]): void;
    unmount(): void;
}
/**
 * Base class for evented nodes in Jacdac
 * @category JDOM
 */
export declare class JDEventSource implements IEventSource {
    /**
     * Gets an internal unique node identifier, mostly used for debugging.
     * @category JDOM
     */
    readonly nodeId: number;
    private readonly listeners;
    /**
     * Gets a counter of event emit calls.
     * @category JDOM
     */
    readonly eventStats: Record<string, number>;
    /**
     * Gets a counter map from events to new listener counts
     * @category JDOM
     */
    newListenerStats: Record<string, number>;
    /**
     * @internal
     */
    constructor();
    /**
     * Registers a handler for one or more events
     * @param eventName name or names of the events to subscribe
     * @param handler handler to register
     * @returns current object instance
     * @category JDOM
     */
    on(eventName: string | string[], handler: EventHandler): this;
    /**
     * Unregisters a handler for one or more events
     * @param eventName name or names of the events to subscribe
     * @param handler handler to unregister
     * @returns current object instance
     * @category JDOM
     */
    off(eventName: string | string[], handler: EventHandler): this;
    /**
     * Registers a handler for one or more events to run only once.
     * @param eventName name or names of the events to subscribe
     * @param handler handler to execute
     * @returns current object instance
     * @category JDOM
     */
    once(eventName: string | string[], handler: EventHandler): this;
    /**
     * Awaits an event with a timeout. Throws JacdacError with timeout if operation does not return.
     * @param eventName
     * @param timeout
     */
    awaitOnce(eventName: string | string[], token?: JDCancellationToken): Promise<void>;
    private addListenerInternal;
    private removeListenerInternal;
    /**
     * Synchronously calls each of the listeners registered for the event named eventName,
     * in the order they were registered, passing the supplied arguments to each.
     * @param eventName
     * @param args
     * @category JDOM
     */
    emit(eventName: string, ...args: unknown[]): boolean;
    /**
     * Gets the number of listeners for a given event
     * @param eventName name of the event
     * @returns number of registered handlers
     * @category JDOM
     */
    listenerCount(eventName: string): number;
    /**
     * Gets the list stack trace where an event was registered. Only enabled if ``Flags.debug`` is true.
     * @param eventName name of the event
     * @returns stack traces where a listener was added
     * @category JDOM
     */
    listenerStackTraces(eventName: string): string[];
    /**
     * Returns an array listing the events for which the emitter has registered listeners.
     * @category JDOM
     */
    eventNames(): string[];
    /**
     * Creates an observable from the given event
     * @param eventName
     * @category JDOM
     */
    observe<T>(eventName: string | string[]): Observable<T>;
    /**
     * Subscribes to an event and returns the unsubscription handler
     * @param eventName
     * @param next
     * @category JDOM
     */
    subscribe<T>(eventName: string | string[], next: (value: T) => void): () => void;
    /**
     * Gets a counter for the ``CHANGE`` event.
     * @category JDOM
     */
    get changeId(): number;
}
export declare class JDSubscriptionScope {
    private unsubscribers;
    private _unmounted;
    get unmounted(): boolean;
    mount(unsubscribe: () => void): () => void;
    unmount(): void;
}
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