import { Event, EventListener } from './event';
import { LeakageMonitor } from './leakage';
import { EventProfiling } from './profiling';
export type EmitterListenerAware = (emitter?: Emitter) => void;
export interface EmitterOptions {
    onFirstListenerAdd?: EmitterListenerAware;
    onFirstListenerDidAdd?: EmitterListenerAware;
    onListenerDidAdd?: EmitterListenerAware;
    onLastListenerRemove?: EmitterListenerAware;
}
export type ScopedListener<T> = EventListener<T> | [EventListener<T>, any];
/**
 * An emitter can be used to emit event.
 *
 * @example
 * ```ts
 * class Example {
 *   private readonly _onMessage = new Emitter<[message: string, sender: string]>();
 *   public readonly onMessage = this._onMessage.event;
 *
 *   public something() {
 *     this._onMessage.emit(["Hello World!", "something"]);
 *   }
 * }
 *
 * const example = new Example();
 *
 * example.onMessage(([message, sender]) => {
 *   console.log(`Message from ${sender}: ${message}`);
 * });
 *
 * example.something();
 * ```
 */
export declare class Emitter<T = any> {
    protected readonly _options?: EmitterOptions;
    protected readonly _leakageMon?: LeakageMonitor;
    protected readonly _perfMon?: EventProfiling;
    protected _disposed: boolean;
    protected _listeners: Set<ScopedListener<T>>;
    protected _deliveryQueue?: [ScopedListener<T>, T][];
    constructor(options?: EmitterOptions);
    get listenerCount(): number;
    /**
     * The event that is controller by this emitter.
     */
    readonly event: Event<T>;
    /**
     * Emit this event.
     * @returns `true` if any listeners have been called.
     */
    emit(data: T): any;
    dispose(): void;
    hasListeners(): boolean;
}