/**
* Custom event emitter implementation for the MCP server
*/
import type { EventEmitter as IEventEmitter, ServerEvents } from '@/types/index.js';
export class EventEmitter implements IEventEmitter<ServerEvents> {
private listeners: Map<keyof ServerEvents, Array<(...args: any[]) => void>> = new Map();
on<K extends keyof ServerEvents>(event: K, listener: (...args: ServerEvents[K]) => void): void {
if (!this.listeners.has(event)) {
this.listeners.set(event, []);
}
this.listeners.get(event)!.push(listener);
}
off<K extends keyof ServerEvents>(event: K, listener: (...args: ServerEvents[K]) => void): void {
const eventListeners = this.listeners.get(event);
if (eventListeners) {
const index = eventListeners.indexOf(listener);
if (index !== -1) {
eventListeners.splice(index, 1);
}
}
}
emit<K extends keyof ServerEvents>(event: K, ...args: ServerEvents[K]): void {
const eventListeners = this.listeners.get(event);
if (eventListeners) {
// Create a copy to avoid issues if listeners are modified during emission
const listenersCopy = [...eventListeners];
for (const listener of listenersCopy) {
try {
listener(...args);
} catch (error) {
// Log error but don't stop other listeners
console.error(`Error in event listener for ${String(event)}:`, error);
}
}
}
}
once<K extends keyof ServerEvents>(event: K, listener: (...args: ServerEvents[K]) => void): void {
const onceWrapper = (...args: ServerEvents[K]): void => {
this.off(event, onceWrapper);
listener(...args);
};
this.on(event, onceWrapper);
}
removeAllListeners<K extends keyof ServerEvents>(event?: K): void {
if (event) {
this.listeners.delete(event);
} else {
this.listeners.clear();
}
}
listenerCount<K extends keyof ServerEvents>(event: K): number {
const eventListeners = this.listeners.get(event);
return eventListeners ? eventListeners.length : 0;
}
eventNames(): Array<keyof ServerEvents> {
return Array.from(this.listeners.keys());
}
getMaxListeners(): number {
return 10; // Default max listeners
}
setMaxListeners(_n: number): this {
// For simplicity, we don't enforce max listeners in this implementation
return this;
}
}
