How to correctly add an element to an object in Vue.JS?

Question

Vue.js

I am trying to add an element to an object but I am getting an error. The function that adds is called addLikedGood()
My code is:

mutations: {
    addLikedGood(state, id) {
      state.likedGood["id_product"] = id;
    }
  },
  getters: {
    getAuth: state => state.auth,
    getAllLikedGood: state => state.likedGood
  },
  state: {
    auth: false,
    likedGood: []
  }
};

Answer 1

addLikedGood(state, id) {
      state.likedGood.push({ id_product: id });
}

Answer 2

I don't fully understand what you are trying to do. Try using Vue.set

Answer 3

likedGood: [] - array .
"id_product" - object key .
Are you sure this is what you want?