Method on

web/lib/collaboration/socket.ts:283–292

(
    type: T["type"],
    handler: EventHandler<T>
  )

  }

  on<T extends CollabEvent>(
    type: T["type"],
    handler: EventHandler<T>
  ): () => void {
    if (!this.handlers.has(type)) {
      this.handlers.set(type, new Set());
    }
    this.handlers.get(type)!.add(handler as EventHandler);
    return () => this.off(type, handler);
  }

  off<T extends CollabEvent>(type: T["type"], handler: EventHandler<T>): void {
    this.handlers.get(type)?.delete(handler as EventHandler);