How to properly implement messaging system on MongoDB/NodeJS?

Question

MongoDB

You need to implement a messaging system with MongoDB/NodeJS. It is necessary that the user sees a list of dialogs with users and, when choosing a dialog, sees the full correspondence with him (following the example of facebook and vkontakte).
Tell me which scheme for storing messages and dialogs to choose?
Do I need to use two collections of Messages and Dialogs and link them by IDs, or should we keep everything in one collection?
Which approach is better for sharding?

Answer 1

I'm afraid to seem ignorant, but still I'll ask: why monga?

Answer 2

At one time I did a similar correspondence for a site using mongo, + I used radish as a message broker for everything. I just had a scheme with separate storage of dialogs and messages themselves.
As for the monga itself, there may have been an unstable release, but it flowed well for me, I’m still afraid to do some serious projects on it, who can know how the situation is now?

Answer 3

I would make a collection of dialogs, and inside them a list of messages