javascript - Mongoose deep populate returning only ID not the entire Object/Array -

this question has been asked death on here, doesn't seem clear cut answer out there.

so have db user has many topics, posts & comments, topic has many posts, , post has many comments.

the adding users, topics, posts & comments working properly. topics being displayed populating posts inside it.(with minor redirection glitch). unable populate comments inside posts. have far.

gettopic method inside topic controller

  gettopic: function(req, res){     console.log("get_topic query", req.body._id)     topic.findone({_id: req.body._id}).populate('posts').populate('posts.comments').exec(function (err, topic) {         if(err){             console.log("something went wrong");             res.json(err)         }else{             console.log(topic);             res.json(topic);         }         })     } 

topic model

var topicschema = new mongoose.schema({   topic: string,   description: string,   category: string,   post_count: number,   user_name: string,   _user: {type: schema.types.objectid, ref: 'user'},   posts: [{type: schema.types.objectid, ref: 'post'}],   created_at: date }); 

post model

var postschema = new mongoose.schema({   post: string,   up_vote: number,   down_vote: number,   user_name: string,   _user: {type: schema.types.objectid, ref: 'user'},   _topic: {type: schema.types.objectid, ref: 'topic'},   comments: [{type: schema.types.objectid, ref: 'comment'}],   created_at: date }); 

comment model

var commentschema = new mongoose.schema({   comment: string,   user_name: string,   _user: {type: schema.types.objectid, ref: 'user'},   _post: {type: schema.types.objectid, ref: 'post'},   created_at: date }); 

find topic.findone working populating "posts", when populating comments, ids show, have console.log in both end , frontend.

as can see hasnt populated arrays, can see [object] in terminal , id's in js console.

what doing wrong?

console.log(json.stringify(topic.posts,undefined,2))

{   "_id": "56b3f865fe0aca747e9dae4f",   "topic": "new topic in new db",   "description": "testing phase 1",   "category": "html",   "user_name": "ani",   "post_count": 0,   "__v": 7,   "posts": [     {       "_id": "56b3f880fe0aca747e9dae50",       "post": "posting answer phase 1",       "user_name": "ani",       "up_vote": 0,       "down_vote": 0,       "created_at": "2016-02-05t01:18:56.709z",       "__v": 3,       "comments": [         "56b40368004a0707806e4b93",         "56b4046beef00e4c82126269",         "56b406656171e44383374cf0"       ]     },     {       "_id": "56b4061a51c0d3f282b89a95",       "post": "answer/post v.2.0",       "user_name": "ani",       "up_vote": 0,       "down_vote": 0,       "created_at": "2016-02-05t02:16:58.575z",       "__v": 1,       "comments": [         "56b4062551c0d3f282b89a96"       ]     } 

console.log(json.stringify(topic,undefined,2))

"posts": [     {       "_id": "56b3f880fe0aca747e9dae50",       "post": "posting answer phase 1",       "user_name": "ani",       "up_vote": 0,       "down_vote": 0,       "created_at": "2016-02-05t01:18:56.709z",       "__v": 3,       "comments": [         "56b40368004a0707806e4b93",         "56b4046beef00e4c82126269",         "56b406656171e44383374cf0"       ]     },     {       "_id": "56b4061a51c0d3f282b89a95",       "post": "answer/post v.2.0",       "user_name": "ani",       "up_vote": 0,       "down_vote": 0,       "created_at": "2016-02-05t02:16:58.575z",       "__v": 1,       "comments": [         "56b4062551c0d3f282b89a96"       ]     } 

you can try using mongoose-deep-populate plugin nested objects

var deeppopulate = require('mongoose-deep-populate');  topic.findone({         _id: req.body._id     }).deeppopulate('posts posts.comments').exec(function (err, topic) {         if (err)             res.json(err)         else{             console.log(topic);             res.json(topic);         };     });