Connect server response to request

[ttmms]

When I have a listener like this.$options.sockets.onmessage = (data) => console.log(data), it triggers on any message from server. How do I know which response is from which request?

Is there some way to have request in a form like this.$socket.send('some data').then(response=> handleResponse(response)) so there would be a connection between specific request and its response?