While using the master branch of sockjs-node, node stopped giving me a stack trace to this line indicating the @session is undefined.

I saw in the code @didMessage checks @session, so perhaps such a check is also necessary in heartbeat_timeout?

While looking at the code I saw some things I did not understand programming-language wise. Can you explain

• how the assignment of supportsheartsbeats works
• where hto_ref comes from?

Thanks