const EventSystem = {
    listeners: new Map(),
    
    on(event, callback) {
        if (!this.listeners.has(event)) {
            this.listeners.set(event, new Set());
        }
        this.listeners.get(event).add(callback);
    },
    
    emit(event, data) {
        if (this.listeners.has(event)) {
            this.listeners.get(event).forEach(callback => callback(data));
        }
    }
};