Resolve MongoDB reference

I am currently building a chatting app with nodejs and mongoDB.
Basically I have two collections to maintain in the db.

user = {
   _id: ObjectId("1234"),
   account: "stan123" 
}

thread = {
  _user:  ObjectId("1234"),
  messages: [
     {
          body:"hi"
          _user:ObjectId("1234")
     },
     {
          body:"second msg"
          _user:ObjectId("1234")
     }
  ]
}

I am planning to pass the thread model with all resolved info (user) to the client side, so that I can construct my widget with it. I searched for solutions for this.Some suggests to make extra calls from client side to get the data. However, I am worried that when the amount of message grows, there will be considerable http calls that might hurt site speed.

I know some drivers can resolve DBRefs automatically and make the code clean. However, according to http://docs.mongodb.org/manual/applications/database-references/

I decided to just use id to maintain reference that make it's as simple as possible.

My plan is resolving all references on server side. Current approach is getting the length of message array first. Then loop through the message array and make a second query to resolve user info separately. In each query callback, do a messageToResolve++ and if(messageToResolve >= thread.messages.length)

If the condition meets, send the resolved model to client and end the response.

This is not a case I would consider embedded because it would be painful when you need to update user data. (message is embedded because it exists only when thread exists)

I am not sure if it's a good way to do it. Does anyone has a better solution?

Sorry if I didn't explain my problem and solution clear enough. And thanks in advance.