Mongoose not saving to database

Question

This REST endpoint updates the favourites list in my database, by removing qname from user.favourites .

My problem is that although updatedUser.favourites is correct at the end of the code, this is not actually being persisted in the database (similar code to add a qname on a separate endpoint do work). I'm sure this is a silly mistake, but what I've written feels intuitively correct.

exports.remQname = function (req, res, next) {
    var userId = req.user.id;
    var qname = req.params.qname;

    console.log('addQname %s %s', userId, qname);
    User.findOne({
        _id: userId
    }, function(err, user) {
        if (err) return next(err);
        if (!user) return res.json(401);

        console.log(user);

        // if the qname already in list, remove it, otherwise add it
        var favourites = user.favourites;
        var matches = _.remove(favourites, function (f) {
            return f == qname
        });
        console.log('Matches: %s %s', matches, favourites);

        user.favourites = favourites;
        user.save(function(err, updatedUser){
            if (err) throw err;
            console.log(updatedUser);  // correct info, but does not reflect database content
            res.status(200).send(updatedUser.favourites);
        });
    });     
};

Here is my Schema

var UserSchema   = new Schema({
    email: String,
    password: String,
    token: String,
    role: {type: String, default: 'user'},
    favourites: Array
});

module.exports = mongoose.model('User', UserSchema);

Answer 1

You can directly remove all instances of a specific value from an array field using $pull , so it would be more efficient to let MongoDB do the work rather than trying to manipulate the array yourself.

User.update({_id: userId},
            {$pull: {favourites: qname}},
            function(err, numberAffected, raw) { ... });

I'd also suggest changing your definition of favourites in the schema to be [String] instead of just Array if it does contain an array of strings.

Answer 2

It had something to do with lodash - this works instead

    var newFavs = _.reject(user.favourites, function (f) {
        return f == qname
    });

    console.log('Favourites - Old: %s New: %s', user.favourites, newFavs);

    // delete user.favourites;
    user.favourites = newFavs;