Sequelize: Append key value to Javascript collection

Good morning everyone!

I’m developing an application with Node.js and Angular, and I’m getting a little stuck lately.

I need to append a custom key -> value to an existing query result collection.

This is the function I have:

exports.findAll = (req, res) => {
    Project.findAll({
            include: [{
                all: true,
                include: [{
                    all: true
                }]
            }]
        })
        .then(data => {
            data.forEach(
                (project) => {
                        // <-------- HERE GOES THE APPEND
                }
            );
            res.send(data);
        })
        .catch(err => {
            res.status(500).send({
                message: err.message || "Error retrieving projects"
            });
        });
};

Description:

After getting the result from the model query, I iterate over each result (aka Project).

Then, what I need to do is append a key -> value pair to that very Project.

By now, I’d like to do something like this:

exports.findAll = (req, res) => {
    Project.findAll({
            include: [{
                all: true,
                include: [{
                    all: true
                }]
            }]
        })
        .then(data => {
            data.forEach(
                (project) => {
                    project.cat = "miaw";
                }
            );
            res.send(data);
        })
        .catch(err => {
            res.status(500).send({
                message: err.message || "Error retrieving projects"
            });
        });
};

This try hasn’t made any changes in my JSON collection, and I don’t know how to accomplish it neither.

Could someone give me some help?
I’ve searched everywhere but couldn’t find anything useful.

Thank you so much!