class CoffeeMaker {
  constructor() {
    // 初始化状态，没有切换任何咖啡模式
    this.state = 'init';
    // 初始化牛奶的存储量
    this.leftMilk = '500ml';
  }
  stateToProcessor = {
    that: this,
    american () {
      // 尝试在行为函数里拿到咖啡机实例的信息并输出
      console.log('咖啡机现在的牛奶存储量是:', this.that.leftMilk)
      console.log('我只吐黑咖啡');
    },
    latte () {
      this.american()
      console.log('加点奶');
    },
    vanillaLatte () {
      this.latte();
      console.log('再加香草糖浆');
    },
    mocha () {
      this.latte();
      console.log('再加巧克力');
    }
  }

  // 关注咖啡机状态切换函数
  changeState (state) {
    this.state = state;
    if (!this.stateToProcessor[state]) {
      return;
    }
    this.stateToProcessor[state]();
  }
}

const mk = new CoffeeMaker();
mk.changeState('latte');