MongoDb remove subdocument from document with nodejs

Question

I have a collection with a following data:

{
       "__v": NumberInt(0),
       "_id": ObjectId("565443b1172e19d51f98b0ed"),
       "address": "tohana",
       "comments": [
         {
           "_id": ObjectId("5654455fe088d89c20736e3c"),
           "comment": "good man",
           "uemail": "dinesh@gmail.com",
           "uname": "dinesh" 
        },
         {
           "_id": ObjectId("565445e471dce6ca20705a84"),
           "comment": "nice person",
           "uemail": "kr@gmail.com",
           "uname": "krishan" 
        },
         {
           "_id": ObjectId("5654460e7aa73bec2064060e"),
           "comment": "bad person",
           "uemail": "Rai",
           "uname": "Rahul" 
        } 
      ],
       "email": "nishantg@ocodewire.com"▼,
       "name": "Nishant" 
    }

Can anyone suggest how to remove a subdocument from a 'comments' key having only id of subdocument, I am going to del? for instance i want to del a subdocument with id 5654455fe088d89c20736e3c So this subdocument should be deleted.

Here is code i am using:

var Users = require("../app/models/users"); //userModel

app.post('/deleteComment/:id', function(req, res) {
    var input = JSON.parse(JSON.stringify(req.body));
    var id = req.params.id;//commentId
    var userId = input.id;//userId

    Users.findByIdAndUpdate(userId, {
      '$pull': {
        'comments':{ '_id': new ObjectId(someStringValue) }
       }
    });
});

But this does not delete data.

Answer 1

Karan,

You would have to make a small adjustment to your code. Your update criteria needs to be wrapped in an object comparing field to key .

app.post('/deleteComment/:id', function(req, res) {
    var commentId = req.params.id; //commentId
    var userId = req.body.id; //userId

    UserAlerts.findOneAndUpdate(
        {userId: userId}, 
        {$pull: {comments: {_id: commentId}}},
        function(err, data){
           if(err) return err;
           console.log(data);
    });
});