Sequelize update a record and it's associations - mysql

Question

I have a model City which hasMany CitiesDescriptions.
I would like to update City, but whenever the data contains CitiesDescriptions I would like them to be updated as well.
This is what my data looks like:
{
"id": 4263,
"name": "Accra",
"country_id": 9,
"slug": "accra-5",
"code": "ACD",
"hdo_code": "",
"tourico_code": null,
"active": true,
"CitiesDescriptions": [
{
"id": 1,
"lang": "es",
"description": "text text"
}
]
}
So, in this case I want the data within CitiesDescriptions to be updated.
In the case that one of the objects inside CitiesDescriptions is a new record (doesn't have ID) I want it to be created.
Anyway, I haven't found a way to do this, whatever I found fails in some way. The closest I found that almost works is this:
var city = models.City.build(params, {
isNewRecord : false,
include : [models.CitiesDescription]
});
Promise.all([
city.save(),
city.CitiesDescriptions.map(function (description) {
if (description.getDataValue('id')) {
return description.save();
} else {
description.city_id = city.id;
return models.CitiesDescription.create(description.dataValues);
}
})
]).then(function(results) {
res.send(results);
});
This works except with the data doesn't have a CitiesDescriptions key.
Still, looks way to complicated to do, specially if tomorrow I have more associated models.
Isn't there any way to do this without so much hassle?
EDIT:
Couldnt find a solution, I made this and it works as intended.
var params = req.body;
var promises = [];
promises.push(models.City.update(params, {
where: {
id: parseInt(req.params.id)
}
}));
if(params.CitiesDescriptions) {
promises.push(
params.CitiesDescriptions.map(function (description) {
return models.CitiesDescription.upsert(description, {individualHooks: true});
})
);
}
Promise.all(promises).then(function(results) {
res.send(results);
});