lodash remove all objects from array. Not following my specification

Question

I have a question when trying to remove a sub-document from MongoDB.

Here is my data structure:

"event" : {
  "_id": "581fec8011acfb28f6bb0b96",
  "participants": [
  {
    "_id": "582041475aa37c0e27fde28b",
    "regDate": "2016-11-07T08:54:31.155Z",
    "group": "board member",
    "lastName": "1",
    "firstName": "test",
    "eventCode": "07e05d"
  },
  {
    "_id": "5820414b5aa37c0e27fde28c",
    "regDate": "2016-11-07T08:54:35.462Z",
    "group": "participant",
    "lastName": "2",
    "firstName": "test",
    "eventCode": "f1685a"
  },
  {
    "_id": "5820414e5aa37c0e27fde28d",
    "regDate": "2016-11-07T08:54:38.441Z",
    "group": "participant",
    "lastName": "3",
    "firstName": "test",
    "eventCode": "a71ec5"
  }
]
}

I tried to use lodash to delete one participant but lodash remove all of my participants. Can you help me to solve this problem?

I updated the whole code at server side where has problem

var alias = req.params.alias;
var pid = req.params.pid; 

    var findAndRemoveParticipant = new Promise ((resolve, reject) => {
        Event.findOne({
            "alias":alias
        },'participants')
        .exec((err, event) => {
            if(err) reject(err)
            else {
                _.remove(event.participants, {_id: pid});
                event.save((err, saved) => {
                    err ? reject(err) : resolve(saved)
                })
            }    
        })
    });

    findAndRemoveParticipant
        .then(saved => {
            res.status(200).json('Participant removed successfully');
        })
        .catch(err => res.status(400).json(err));

In client side I use the same code, and it work

$http.delete(_deleteParApi)
        .success(msg => {
            $scope.parRemoved = msg;
            _.remove($scope.participants,{_id: pid})
        })  
        .catch(err => {
            console.log(err);
        })

score 0 · Answer 1 · edited May 23 '17 at 10:27

Do this

MODEL.find(YOUR QUERY).lean().exec(function(err, data){
// MODIFY DATA NOW AND SAVE IT
})

DUPLICATE QUESTION

OR

Mongoose Models inherit from Documents, which have a toObject() method. I believe what you're looking for should be the result of doc.toObject().

take a look

var pid = req.params.pid;/
event.toObject()
event.participants = _.remove(event.participants,{_id: pid})
console.log(event.participants);
// []
event.save((err,saved) => {
    err ? reject(err) : resolve(saved)
}

Ben · Answer 2 · 2016-11-07T13:06:26.733

According to the lodash document, it removes the matched items from the array and returns an array of the removed elements, so you don't need to assign it back to event.participants but if you do, you need to check for 'not equal' to get the returned array you want. Here is the revised code:

var pid = req.params.pid;
event.participants = _.remove(event.participants,function(o) {
  return o._id !== pid;
});
console.log(event.participants);

Here is the output if pid = '582041475aa37c0e27fde28b':

[{ 
    _id: '5820414b5aa37c0e27fde28c',
    regDate: '2016-11-07T08:54:35.462Z',
    group: 'participant',
    lastName: '2',
    firstName: 'test',
    eventCode: 'f1685a' 
}, { 
    _id: '5820414e5aa37c0e27fde28d',
    regDate: '2016-11-07T08:54:38.441Z',
    group: 'participant',
    lastName: '3',
    firstName: 'test',
    eventCode: 'a71ec5' 
}]

score 0 · Accepted Answer · answered Nov 07 '16 at 12:56

0

use mongo $pull :

 Event.update(
    {"alias":alias},
    { $pull: { 'participants': { _id: pid } } }
);

answered Nov 07 '16 at 12:56

Daphoque

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Thank you for that, I solved my problem. But I still not understand why lodash not work in my situation. That so weird. – Giang Đỗ Hoàng Nov 08 '16 at 02:08

lodash remove all objects from array. Not following my specification

3 Answers3