I have a store object i retrieved from mongodb,
I am interested in using the value store.comments.

i logged the store value and it is:

```
store:{ _id: 57e246f73e63d635cce3d174,
  __v: 0,
  comments: 57e246f73e63d635cce3d177,
  loc: [ 105.832321, 105.233272 ],
  name: '24 store',
  reportedFalse: [],
  products: [],
  currentRanking: 
   { likes: 57e246f73e63d635cce3d175,
     dislikes: 57e246f73e63d635cce3d176 },
  timePosted: Wed Sep 21 2016 11:38:15 GMT+0300 (Jerusalem Summer Time) },

```

then i logged the value of the object comments value - **result.comments**:

```
store comments objectid: undefined

```

and it seems when i try to search later by the comments value that it doesn't succeed in searching with it. because the search returns null, although i see that in my db i have a corresponding object in "comments" table/schema with the same id....

```
Comments.findById(commentsId,function(commentsErr,commentsArrObj){
...
cb(null, commentsArrObj._id);
                    }

```

i get:

```
TypeError: Cannot read property '_id' of null

```

heres part of my schema for reference:

```
        name: String,
        comments: mongoose.Schema.Types.ObjectId, // each comment has a object id - responder, link curl? crud?  to his profile, profile pic, date time.
        timePosted : { type: Date, default: Date.now },
        currentRanking: {
            likes: mongoose.Schema.Types.ObjectId, // a votes document
            dislikes: mongoose.Schema.Types.ObjectId // a votes document
        },

```