Question

$.connection.hub.error(function (err) {
                alert("Error signalR:" + JSON.stringify(err));
            });

What can I use this function for? It always displays this more often when running on mobile devices, and it never provides any information. So how do you use it?

I never experiences SignalR breaking down because of this either, so should I just comment it out?

Answer 1

For runtime cases .error is useful in unique browser/client scenarios that don’t work with your implementation. For instance, lets say you have an application that requires SignalR to only use the web sockets or server sent events transports:

$.connection.hub.start(["serverSentEvents","webSockets"]);

This means that SignalR will not be able to successfully start a connection in < IE 10. So utilizing .error in this scenario will allow you to notify a user that they do not have real time capability enabled due to their browser choice.

Ultimately it becomes useful based on what you’re trying to accomplish. One additional example is that dfowler in JabbR uses it to clear his “pending message” queue https://github.com/davidfowl/JabbR/blob/master/JabbR/Chat.js#L978.

Hope this helps!