Mongoose delete array element in document and save

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.

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/

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.

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.
)

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);
    });
};

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.

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; :)

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)
    }
});

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