Making edits to .then() in a Promise

Question

I have this sequelize controller below:

const Category = require('../models').category;

module.exports = {
  list(req, res) {
    return Category
      .all({attributes: ['title']})
      .then(categories => res.status(200).send(categories))
      .catch(error => res.status(400).send(error));
  }
};

Essentially, returning Category.all({attributes: ['title']}) results in this array:

[
  {"title": "video"},
  {"title": "gif"},
  {"title": "website"}
]

I want to add the object {"title": "all"} to the beginning of the array, by doing something like this:

const Category = require('../models').category;

module.exports = {
  list(req, res) {
    return Category
      .all({attributes: ['title']})
      .then(categories => 
        categories.unshift({"title": "all"})
        res.status(200).send(categories)
      )
      .catch(error => res.status(400).send(error));
  }
};

But I know this is not exactly correct. How, when handling promises and the .then() statement, can I edit the categories array in the .then() statement? Thanks!

Answer 1

.then(categories => {
        categories.unshift({"title": "all"})
        res.status(200).send(categories)
      })

Just need to add curly braces around the code in the then statement so it’s not an implied return.