I've just completed the simple chat client socket.io tutorial and I am inspecting the messages going between my browser and the Node.js server web socket using the Chrome WebSocket inspector. There are numbers prefixed before the messages as depicted in my screenshot below.
As you can see there are messages with just '2' and '3' and next to my emits there are 42s going back and forth. What do they mean? Is there a list of the main message types I should familiarise myself with so I can learn about debugging Web Sockets?