ChristmasEmitter

[KP1976]

export class ChristmasEmitter {
  private listeners: Record<string, Function[]> = {};

  on(event: string, listener: Function) {
    this.listeners[event] = this.listeners[event] || [];
    this.listeners[event].push(listener);

    return () => {
      this.listeners[event] = this.listeners[event].filter(
        (l) => l !== listener
      );
    };
  }

  emit(event: string, ...args: any[]) {
    this.listeners[event]?.forEach((listener) => listener(...args));

    return this;
  }

  off(event: string, listener?: Function) {
    if (!listener) {
      delete this.listeners[event];
    } else {
      this.listeners[event] = this.listeners[event].filter(
        (l) => l !== listener
      );
    }

    return this;
  }
}