lean() inside populate in mongoose

Question

I am populating a user collection in mongoose and want to set a flag if the user is signed up using social accounts. So I am selecting that fields in populate. But due to security concerns I don't want to pass it in response. So I converted it into plain object using lean() and set the values as null. But once a values are set null for a particular user then it set that values null for that user_id. How set them null or how to hide them from response.

 Pins.find(condition)
   .limit(limit)
   .sort({time: -1})
   .populate({
     path: 'user_id',
     select: '_id name pic twitter_id fb_id',
     options: { lean: true}
   })
   .lean()
   .exec(function(err, data) {

        if(data){
         var flag = 0
            async.eachSeries(data, function(v, callback1) {

              if(v.user_id.twitter_id || v.user_id.fb_id ){
                  v.socialaccount=1
                  v.user_id.fb_id =''
                   v.user_id.twitter_id =''
              }else{
                  v.socialaccount=0 
                      v.user_id.fb_id =''
                   v.user_id.twitter_id =''
              }
             callback1()



     },function(){
              console.log(data)
             callback(data)  

            })

        } else {
            callback(data)
        }

    })

Thanks in advance

Answer 1

Here it is.

Pins.find(condition)
  .limit(limit)
  .sort({time: -1})
  .populate({
    path: 'user_id',
    select: '_id name pic twitter_id fb_id',
    options: { lean: true}
  })
  .lean().exec(function(err, pins) {
  if(pins){

    pins = _.map(pins,function(pin) {

      //Setting the flag for social account
      pin.socialaccount = (pin.user_id.twitter_id || pin.user_id.fb_id );

      //Omitting the twitter_id and fb_id fields from user_id object
      pin.user_id.twitter_id = undefined;
      pin.user_id.fb_id = undefined;
      return pin;
   });

   return res.send(pins);
 }

})

I have mapped the pins collection from the find query such that you can set your socialaccount flag and can set the properties not required to undefined

However i am not sure if you can use _.omit(pin.user_id,'twitter_id') instead of pin.user_id.twitter_id = undefined.Need to test that !

The result pins collection will now have other user properties you wanted. Hope it helps :)