How to implement rooms for private messages like in VK?

Question

Socket.io

I would be grateful if you could help me how to implement unique message rooms, now I made it so that if the user enters /dialog/user id, then I create a room with my id + user id, and so that there is no problem of two different rooms, I created an entry in db for each priority it has the form Math.random () * 100, I did this in order to compare the priority and who has a higher priority goes to the first position, and who has less, his id becomes at the end,
example if(my.priority > user.priority) room = my.id + user.id, then I save the room record in db, but the problem is that I have to duplicate the code, that is, after if I write else user.id + my.id, everything works fine, but I have to duplicate the code in if and else , I would like not to write this shit code, and I want to ask how can I do something similar to a chat in VK, you enter the chat and the link becomes im? sel? and here is the id of a person, and when they come to you there is already my id

Answer 1

A private chat has 2 parameters sender and recipient and up to a bunch of names. Actually, you need to bring all this into one line, select it, check the user and give the chat