#构建者模式(Builder)

class Starbucks {
  constructor() {}
  create(builder) {
    builder.step1();
    builder.step2();
    builder.step3();
    return builder.get();
  }
}

class Americano {
  constructor() {
    this.water = null;
    this.coffee = null;
  }
  addCoffee() {
    this.coffee = "20g";
  }
  addWater() {
    this.water = "400ml";
  }
}

class AmericanoBuilder {
  constructor() {
    this.drink = null;
  }
  step1() {
    this.drink = new Americano();
  }
  step2() {
    this.drink.addCoffee();
  }
  step3() {
    this.drink.addWater();
  }
  get() {
    return this.drink;
  }
}

export { Starbucks, AmericanoBuilder };

let starbucks = new Starbucks();
let americanoBuilder = new AmericanoBuilder();
starbucks.create(americanoBuilder);