Create or Update Sequelize

I'm using Sequelize in my Nodejs project and I found a problem that I'm having a hard time to solve. Basically I have a cron that gets an array of objects from a server than inserts it on my database as a object ( for this case, cartoons ). But if I already have one of the objects, I have to update it.

Basically I have a array of objects and a could use the BulkCreate() method. But as the Cron starts again, it doesn't solve it so I was needing some sort of update with an upsert true flag. And the main issue: I must have a callback that fires just once after all these creates or updates. Does anyone have an idea of how can I do that? Iterate over an array of object.. creating or updating it and then getting a single callback after?

Thanks for the attention

From the docs, you don't need to query where to perform the update once you have the object. Also, the use of promise should simplify callbacks:

Implementation

function upsert(values, condition) {
    return Model
        .findOne({ where: condition })
        .then(function(obj) {
            // update
            if(obj)
                return obj.update(values);
            // insert
            return Model.create(values);
        })
}

Usage

upsert({ first_name: 'Taku' }, { id: 1234 }).then(function(result){
    res.status(200).send({success: true});
});

Note

1. This operation is not atomic.
2. Creates 2 network calls.

which means it is advisable to re-think the approach and probably just update values in one network call and either:

1. Look at the value returned (i.e. rows_affected) and decide what to do.
2. Return success if update operation succeeds. This is because whether the resource exists is not within this service's responsibility.