How to manage errors if port is already used

[leonardospeca]

Hello, I would like to know how to manage errors if the port is already used, for example, now I'm getting this error and I can't "catch" it:
The HTTP/S server is already being used by another WebSocket server

Maybe it could be useful make the initWsServer return a promise, or add a callback to manager errors

Thank you

[mukhopj]

i get stuck in this. I also need the answer