First time using websockets with Go and getting a weird error that doesn't break the program, and still continue as if it was not a problem. The client is a ReactJS single page application.

JS Client:

 const socket = new WebSocket("ws://localhost:5000/ws");
            setConnection(socket);

            socket.onmessage = (e) => {
                const message = JSON.parse(e.data)
                console.log("message:", message)
          
                switch (message.Command) {
                  case "loginResult":
                    if (message.Result) {
                      console.log("login worked");
                    }else{
                      console.log("login did not work");
                    }
                    break;
                }
              }

Snippet of Go it is getting JSON from:

result := ws.LoginResult{
        BaseMessage: ws.BaseMessage{
            Command: "loginResult",
        },
        Result: false,
    }

b, err := json.Marshal(result)

if err != nil {
    fmt.Println(err)
    return
}

if err = conn.WriteMessage(msgType, b); err != nil {
    return
}

And the output:

in here
WebsocketProvider.tsx:20 message: {Command: 'loginResult', Result: false}
WebsocketProvider.tsx:27 login did not work
VM3502:1 Uncaught SyntaxError: Unexpected token l in JSON at position 0
    at JSON.parse (<anonymous>)
    at WebSocket.socket.onmessage (WebsocketProvider.tsx:19)
socket.onmessage @ WebsocketProvider.tsx:19

Anyone have any idea why this is the case?

Solution was found:

• It was to do with the migration of code and that a left over line was making a call that was ignored, hence where it made no difference to the execution. Nothing to do with the JSON format being difference since this was automatically generate by Go libraries.