problem_fetching.js

/** 
Adding relationship. Pretty neat.

Let's say I have a User in var user1, user2:
**/
var friends = new UserFriends();
friends.users = [user2._id,user1._id];
friends.save();

/**
Fetching friends. Not as neat.

Let's say I have a User object in the var `usr`, now I want to fetch all their friends
**/


// I came up with this function

function findFriendsOf(myUser, _callback) {
	console.log("Looking for friends of", myUser.user, myUser._id);
	UserFriends.find({users: myUser._id},function(err, friends) {
	
		var friendsIds = [];
		// Let's look through our friends and gather an array with our friends' user ids
		for (var i in friends) {
			var user1 = friends[i].users[0];
			var user2 = friends[i].users[1];
			
			friendsIds.push(myUser._id != user1
				? user1
				: user2
			);
			
		}
	
	
		User.find({_id: {$in: friendsIds}}, function(err, users) {
			// Finally, here should we have all our friends in var users
			_callback(err, users);
		})
	});
}


findFriendsOf(usr, function(err,users) {
	console.log("users:",users);
});

UserFriendsSchema.js

var mongoose = require('mongoose'),
	Schema	 = mongoose.Schema,
	User 	 = require('./UserSchema');

var FriendsSchema = new Schema({
	users		: [User.ObjectId], 
	confirmed	: { type: Boolean, default: false, index: true },
	
	created		: {type: Date, default: Date.now},
	
});
FriendsSchema.index({users: 1}, {unique:true}); // Fine, ensures we only have one of these relations
module.exports = FriendsSchema;

UserSchema.js

var UserSchema = new Schema({
	user		: { type: String, unique: true, validate: /^[A-Z0-9._%+-]+$/i },
	password	: { type: String, index: true, set: setPassword },
	email		: { type: String, unique: false, set: toLower, validate: /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i },
	confirmed	: { type: Boolean, default: false, index: true },
	apiKey		: { type: String, unique: true },
	
	created		: {type: Date, default: Date.now},
	modified	: {type: Date, default: Date.now},
	
	name: {
		first: String,
		last: String
	}
	
});