burger-maker.js

// {} object literal
// "" string literal
// 23 number literal
// [] array literal

function makeBurger(pattyType) {
  return {
    pattyType: pattyType,
    toppings: [],
    addTopping: function (topping) {
      this.toppings.push(topping);
      console.log(this, this.toppings);
    }
  };
}

console.log(cheeseBurger.toppings);