How to do aggregation correctly?

Question

MongoDB

There are room, message and user documents.

room {
_id,
creatorId
}
message {
_id,
roomId,
contactId
}
user {
_id
}

I need to get all rooms that match a user, all messages that match a room, and all users that match a contactId in a message. I got rooms and messages, there are no problems here, but I don’t know how to get contacts. At the moment I have this response structure:

[{
_id,
messages: [{
_id,
contactId
},
...
]
},
...]

As I understand it, I need to unwind messages, lookup for contacts and then group everything, but it doesn’t work.

Answer 1

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