Decorator design pattern example

dp-decorator.js

// Design Patterns: Decorator
class Drink {
  constructor() {
    this.total = function() {
      return 0;
    }
  }
}

// decorator 1
const Rum = (drink) => {
  let t = drink.total();
  drink.total = () => {
    return t + 4;
  }
}

// decorator 2
const Sugar = (drink) => {
  let t = drink.total();
  drink.total = () => {
    return t + .5;
  }
}

// decorator 3
const Lime = (drink) => {
  let t = drink.total();
  drink.total = () => {
    return t + 1.5;
  }
}

// decorator 4
const Soda = (drink) => {
  let t = drink.total();
  drink.total = () => {
    return t + 3;
  }
}

let drink = new Drink();
Rum(drink);
Sugar(drink);
Lime(drink);
Soda(drink);
console.log(`Mojito price: $${drink.total()}`);