/**
* Event Bus
* Simple event system using Node.js EventEmitter
*/
import { EventEmitter } from 'events'
export type EventHandler<T = any> = (data: T) => void
export class EventBus<T = any> {
private emitter: EventEmitter
constructor(maxListeners: number = 100) {
this.emitter = new EventEmitter()
this.emitter.setMaxListeners(maxListeners)
}
/**
* Subscribe to an event
* Returns an unsubscribe function
*/
on(event: string, handler: EventHandler<T>): () => void {
this.emitter.on(event, handler)
return () => {
this.emitter.off(event, handler)
}
}
/**
* Unsubscribe from an event
*/
off(event: string, handler: EventHandler<T>): void {
this.emitter.off(event, handler)
}
/**
* Emit an event
*/
emit(event: string, data: T): void {
this.emitter.emit(event, data)
}
/**
* Subscribe to an event once
* Returns an unsubscribe function
*/
once(event: string, handler: EventHandler<T>): () => void {
this.emitter.once(event, handler)
return () => {
this.emitter.off(event, handler)
}
}
/**
* Get the number of listeners for an event
*/
listenerCount(event: string): number {
return this.emitter.listenerCount(event)
}
/**
* Remove all listeners for an event (or all events if not specified)
*/
removeAllListeners(event?: string): void {
this.emitter.removeAllListeners(event)
}
/**
* Get all event names that have listeners
*/
eventNames(): (string | symbol)[] {
return this.emitter.eventNames()
}
}
/**
* Create a typed event bus instance
*/
export function createEventBus<T = any>(maxListeners?: number): EventBus<T> {
return new EventBus<T>(maxListeners)
}
/**
* Global event bus instance (singleton)
*/
let globalEventBus: EventBus | null = null
export function getGlobalEventBus<T = any>(): EventBus<T> {
if (!globalEventBus) {
globalEventBus = new EventBus()
}
return globalEventBus as EventBus<T>
}
