Mongoose delete array element in document and save - node.js

Question

I have an array in my model document. I would like to delete elements in that array based on a key I provide and then update MongoDB. Is this possible?
Here's my attempt:
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var favorite = new Schema({
cn: String,
favorites: Array
});
module.exports = mongoose.model('Favorite', favorite, 'favorite');
exports.deleteFavorite = function (req, res, next) {
if (req.params.callback !== null) {
res.contentType = 'application/javascript';
}
Favorite.find({cn: req.params.name}, function (error, docs) {
var records = {'records': docs};
if (error) {
process.stderr.write(error);
}
docs[0]._doc.favorites.remove({uid: req.params.deleteUid});
Favorite.save(function (error, docs) {
var records = {'records': docs};
if (error) {
process.stderr.write(error);
}
res.send(records);
return next();
});
});
};
So far it finds the document but the remove nor save works.

Answer 1

You can also do the update directly in MongoDB without having to load the document and modify it using code. Use the $pull or $pullAll operators to remove the item from the array :
Favorite.updateOne({ cn: req.params.name }, {
$pullAll: {
favorites: req.params.deleteUid,
},
});
To remove objects from array then
Favorite.updateOne({ cn: req.params.name }, {
$pullAll: {
favorites: [{_id: req.params.deleteUid}],
},
});
(you can also use updateMany for multiple documents)
http://docs.mongodb.org/manual/reference/operator/update/pullAll/

Answer 2

The checked answer does work but officially in MongooseJS latest, you should use pull.
doc.subdocs.push({ _id: 4815162342 }) // added
doc.subdocs.pull({ _id: 4815162342 }) // removed
https://mongoosejs.com/docs/api.html#mongoosearray_MongooseArray-pull
I was just looking that up too.
See Daniel's answer for the correct answer. Much better.

Answer 3

Answers above are shown how to remove an array and here is how to pull an object from an array.
Reference: https://docs.mongodb.com/manual/reference/operator/update/pull/
db.survey.update( // select your doc in moongo
{ }, // your query, usually match by _id
{ $pull: { results: { $elemMatch: { score: 8 , item: "B" } } } }, // item(s) to match from array you want to pull/remove
{ multi: true } // set this to true if you want to remove multiple elements.
)

Answer 4

Since favorites is an array, you just need to splice it off and save the document.
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var favorite = new Schema({
cn: String,
favorites: Array
});
module.exports = mongoose.model('Favorite', favorite);
exports.deleteFavorite = function (req, res, next) {
if (req.params.callback !== null) {
res.contentType = 'application/javascript';
}
// Changed to findOne instead of find to get a single document with the favorites.
Favorite.findOne({cn: req.params.name}, function (error, doc) {
if (error) {
res.send(null, 500);
} else if (doc) {
var records = {'records': doc};
// find the delete uid in the favorites array
var idx = doc.favorites ? doc.favorites.indexOf(req.params.deleteUid) : -1;
// is it valid?
if (idx !== -1) {
// remove it from the array.
doc.favorites.splice(idx, 1);
// save the doc
doc.save(function(error) {
if (error) {
console.log(error);
res.send(null, 500);
} else {
// send the records
res.send(records);
}
});
// stop here, otherwise 404
return;
}
}
// send 404 not found
res.send(null, 404);
});
};

Answer 5

This is working for me and really very helpful.
SubCategory.update({ _id: { $in:
arrOfSubCategory.map(function (obj) {
return mongoose.Types.ObjectId(obj);
})
} },
{
$pull: {
coupon: couponId,
}
}, { multi: true }, function (err, numberAffected) {
if(err) {
return callback({
error:err
})
}
})
});
I have a model which name is SubCategory and I want to remove Coupon from this category Array. I have an array of categories so I have used arrOfSubCategory. So I fetch each array of object from this array with map function with the help of $in operator.

Answer 6

keywords = [1,2,3,4];
doc.array.pull(1) //this remove one item from a array
doc.array.pull(...keywords) // this remove multiple items in a array
if you want to use ... you should call 'use strict'; at the top of your js file; :)

Answer 7

I used this format for my project and it's worked
router.delete('/dashboard/participant/:id', async (req, res, next) => {
try {
const participant = await Participant.findByIdAndDelete({ _id: req.params.id });
// { $pull: { templates: { _id: templateid } } },
const event = await Event.findOneAndUpdate({ participants: participant._id }, { $pull: { participants: participant._id } }, { new: true });
res.status(200).json({ request: 'Deleted', participant, event });
} catch (error) {
res.json(error)
}
});

Answer 8

Favorite.update({ cn: req.params.name }, { "$pull": { "favorites": { "_id": favoriteId } }}, { safe: true, multi:true }, function(err, obj) {
//do something smart
});