nodeJS create dynamic array and use as response

Question

Hi i am creating an empty array then populating it with data from a mongo query using a forEach Loop.

i have been attempting this now for 4 days and nothing i seem to do is working i know im close but being a newbie to javascript and MEAN stack i just cant figure it out.

i have attached the code with comments on everything i am trying to do.

please any help would be awesome..

var mongoose = require('mongoose'),
    User = require('../../models/UserModel'),
    async = require('async');


module.exports.getfollowing = function(req, res){

    //grab the Users ID from the body
    var thefollower = req.body.follower;

    //create empty array that i want to populate with the followee's ID and Avatar url
    var obj = [];

    //query mongo for the user
    User.findOne({ _id: thefollower }, function (err, user) {

            if (err) {

                console.log(err);
                res.json(err); 

            } else {

                //grab the following element of the users mongo schema -- should return all the followee's ID's -- tested works
                var following = user.following;

                //iritate throught all the followee's
                async.forEach(following, function(item, callback) {

                    //current followee
                    var user = item;

                    //query mongo for the followee
                    User.findOne({_id: user}, function(err, followee, callback){

                        //get followee's ID and Avatar url
                        var id = followee._id;
                        var avatar = followee.avatar;


                       //add the followee's ID and Avatar url to the obj array 
                       obj.push({                
                            id: id,
                            avatar: avatar                 
                       });

                    }); 

                    //see if this worked - returns empty
                    console.log(obj);
                    callback();

                }, function(err) {

                    //see if this worked - returns empty
                    console.log(obj);

                    //respond to the client - returns empty
                    res.json(obj);  

                });                  
            }   
    });  
};

Answer 1

mscdex

Was spot on his answer solved my issue for future help to others here is the code

var mongoose = require('mongoose'),
    User = require('../../models/UserModel'),
    async = require('async');


module.exports.getfollowing = function(req, res){

    //grab the Users ID from the body
    var thefollower = req.body.follower;

    //create empty array that i want to populate with the followee's ID and Avatar url
    var obj = [];

    //query mongo for the user
    User.findOne({ _id: thefollower }, function (err, user) {

            if (err) {

                console.log(err);
                res.json(err); 

            } else {

                //grab the following element of the users mongo schema -- should return all the followee's ID's -- tested works
                var following = user.following;

                //iritate throught all the followee's
                async.forEach(following, function(item, callback) {

                    //current followee
                    var user = item;

                    //query mongo for the followee
                    User.findOne({_id: user}, function(err, followee){

                        //get followee's ID and Avatar url
                        var id = followee._id;
                        var avatar = followee.avatar;


                       //add the followee's ID and Avatar url to the obj array 
                       obj.push({                
                            id: id,
                            avatar: avatar                 
                       });

                    //see if this worked - returns empty
                    console.log(obj);
                    callback();

                    }); 


                }, function(err) {

                    //see if this worked - returns empty
                    console.log(obj);

                    //respond to the client - returns empty
                    res.json(obj);  

                });                  
            }   
    });  
};

Answer 2

You need to move your callback(); that is at the end of your async.forEach() callback to inside the User.findOne({_id: user}, ...) callback (right after you call obj.push()) because that is when you are actually done with item. With your current code you are telling the async module immediately that you are done with item, before your mongo query has a chance to complete.