/**
 * Type-safe event emitter for chart events
 */
export declare class EventEmitter<EventMap extends object> {
    private listeners;
    /**
     * Subscribe to an event
     */
    on<K extends keyof EventMap>(event: K, handler: (data: EventMap[K]) => void): void;
    /**
     * Unsubscribe from an event
     */
    off<K extends keyof EventMap>(event: K, handler: (data: EventMap[K]) => void): void;
    /**
     * Emit an event with data
     */
    emit<K extends keyof EventMap>(event: K, data: EventMap[K]): void;
    /**
     * Subscribe to an event once
     */
    once<K extends keyof EventMap>(event: K, handler: (data: EventMap[K]) => void): void;
    /**
     * Remove all listeners
     */
    clear(): void;
    /**
     * Get listener count for an event
     */
    listenerCount(event: keyof EventMap): number;
}