json - Inserting elements in array mongoose creates Object in NodeJS -

i'm trying insert documents in array using mongoose.

here's schema:

var user = new mongo.schema({   _id : number,   devices:[       {         device_id : string,         type : string       }     ]}) 

the update code in nodejs looks like:

app.put('/user/update',function(req,res){     var obj = req.body;     users.update(         {'user.username' : obj.email},         {             'user.username' : obj.email,              'user.password' : obj.password,              'user.name.first' : obj.name,              'user.department' : obj.department,              'user.year' : obj.year,              'user.college' : obj.college,             'user.contact.phone': obj.contact,               'user.last_login' : obj.last_login,             $push:{                  'devices': {                      device_id: 'sadasd32u4je3bdjas',                       type: 'windows'                 }             }          }, function(err){                 if(err)                      res.json({"foo": string(err)});                 else                     res.json({"foo": "successfully signed up!"});          });     } ); 

but instead inserts like:

"devices": [             "[object object]",             "[object object]",             "[object object]",             "[object object]",             "[object object]"          ], 

where did go wrong? again.

use findoneandupdate() method 'upsert' option set true - creates object if doesn't exist (defaults false):

var obj = req.body; var query = {'user.username': obj.email}; var doc = {     $set: {         'user.username': obj.email,          'user.password': obj.password,          'user.name.first': obj.name,          'user.department': obj.department,          'user.year': obj.year,          'user.college': obj.college,         'user.contact.phone': obj.contact,           'user.last_login': obj.last_login       },     $push: {          'devices': {              device_id: 'sadasd32u4je3bdjas',               type: 'windows'          }     } }; var options = {upsert: true}; users.findoneandupdate(query, doc, options, function(err){     if(err)          res.json({"foo": string(err)});     else         res.json({"foo": "successfully signed up!"});  });