• Reproduce race condition error with LoroWebsocketClient when mounting in effect in react strict mode via unit test
• Fix the race condition

Explanation

In development, react has a thing called "strict mode" which mounts, then unmounts, then re-mounts all components.

sendJoinPayload calls void this.connect() as a fallback retry. connect() unconditionally sets shouldReconnect = true, which resurrects a client that was intentionally closed via close(). This manifests in React strict mode where useEffect creates a client + joins a room, and the cleanup function calls close() but a deferred microtask from resolveAuth().then(sendJoinPayload) fires after close(), calling connect() and creating a zombie WebSocket connection.

A piece of sample code that would cause this fire is:

useEffect(() => {
    const client = new LoroWebsocketClient({ url: "ws://localhost:3000" });
    void client.connect();
    client.join({ roomId: "my-room", crdtAdaptor: new LoroAdaptor() });

    return () => {
      client.close();
    };
  }, []);