How to loop through an array in mongodb?

Question

How to loop through an array in mongodb?

This is my code to loop through the results for Users and then I am trying to loop through the friend request array made by the search from the user. However, I keep getting a TypeError: cannot read property '$elemMatch of undefined. I am using mongoose and Node.Js and this searchPost is in the route folder.

exports.searchPost = function(req, res, err) {
    User.find({$or:[
            {firstName: req.body.firstName},
            {lastName: req.body.lastName},
            {email: req.body.email},
            {phone: req.body.phone}]
    }, function(err, users, userAdd) {
        if(err) {

            return res.render('searchError', {title: 'Weblio'}); 
        } else {

            if(req.body.firstName=== '' && req.body.lastName==='' && req.body.email==='' && req.body.phone=== '') {
                return res.render('searchError', {title: 'Weblio'});        
            } else {

                    for(x in users) {

                        User.findById(req.signedCookies.userid, 
                            {friendRequest: x.id}
                                if(x.id === true ) {
                                    console.log('addman1'); 
                                    return userAdd = false;
                                } else {
                                    console.log('addman2');
                                    return userAdd = true;
                                }

                            });

                        }       


                return res.render('searchResults', {title: 'Weblio',        
                    usersFound: users, 
                    userAdded: userAdd
                });
            } 
        }
    });

};

Error:

TypeError: Cannot read property '$elemMatch' of undefined
    at Query._castFields (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoos
e\lib\query.js:2203:22)
    at Query.findOne (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\li
b\query.js:1775:25)
    at Function.findOne (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose
\lib\model.js:944:16)
    at Function.findById (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoos
e\lib\model.js:882:15)
    at Promise.<anonymous> (C:\Users\Lior\Desktop\nodep\test5\routes\user.js:193
:12)
    at Promise.<anonymous> (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongo
ose\node_modules\mpromise\lib\promise.js:162:8)
    at Promise.EventEmitter.emit (events.js:95:17)
    at Promise.emit (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\nod
e_modules\mpromise\lib\promise.js:79:38)
    at Promise.fulfill (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\
node_modules\mpromise\lib\promise.js:92:20)
    at C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\lib\query.js:1725
:26
[ERROR] 17:23:30 TypeError

node.js
mongodb
mongoose

Answer 1

I think you might be trying to do something like this

var totalDocsToProcess = users.length;

for(var i = 0; i < users.length; i++) {
  User.findById(req.signedCookies.userid, function(err, x) {
    totalDocsToProcess = totalDocsToProcess - 1;

    if(x.id === true ) {
      console.log('addman1'); 
      return userAdd = false;
    } else {
      console.log('addman2');
      return userAdd = true;      
    }

    if(totalDocsToProcess == 0) {
      return res.render('searchResults', {title: 'Weblio',        
        usersFound: users, 
        userAdded: userAdd
      });      
    }
  })
}

Answer 2

for(x in users) x is the key of the array not the value, you should try:

for(var i = 0; i < users.length; ++i) { 
    var x = users[i]; etc etc