javascript - 未捕获的ReferenceError:未定义makeDrink

当我使用buyDrink（）方法运行代码时，它被认为是可行的。
但是，如果不对方法进行注释，则不是。我试图在几个小时内解决问题，但没有成功。
请问你能帮帮我吗？
谢谢。

var coffeeShop = {
    beans: 40,
    money: 100,
    beanCost: 2,

    drinkRequirements: {
        latte: {
            beansRequirements: 10,
            price:  5
        },
        americano: {
            beansRequirements: 5,
            price:  2.5
        },
        doubleShot: {
            beansRequirements: 15,
            price:  7.5
        },
        frenchPress: {
            beansRequirements: 12,
            price:  6
        }
    },


    buySupplies: function(numBeansBought) {
        if (this.money - (numBeansBought*this.beanCost) >= 0)
        {
          this.money-= numBeansBought*this.beanCost;
          this.beans+=numBeansBought;
        }
    },


    makeDrink: function(drinkType) {
        /*
        How to check if value exists in an object
        Let's consider an example which would answer this question
        var priceOfFood = { pizza: 14, burger 10 }
        priceOfFood.hasOwnProperty('pizza') // true
        priceOfFood['pizza'] // 14
        priceOfFood.hasOwnProperty('chips') // false
        priceOfFood['chips'] // undefined

        */
        //if (this.drinkRequirements.hasOwnProperty(drinkType) === false)
        if (!this.drinkRequirements[drinkType])
        {
            alert("Sorry, we don't make "+ drinkType);
            return false;
        }
        else
        {
            var beansRest =  0;
            beansRest = this.beans - this.drinkRequirements[drinkType].beansRequirements;
            if (beansRest < 0)
            {
              alert("Sorry, we're all out of beans!");
              return false;
            }
            else
            {
                this.beans = beansRest;
                return true;
            }
        }
    }

    ,
    buyDrink: function(drinkType) {
        if (makeDrink(drinkType))
        {
            this.money+= drinkRequirements[drinkType].price;
            console.log('the new coffeeShop money is ' + this.money);
        }
    }

}

coffeeShop.makeDrink("latte");
console.log("latte, " + coffeeShop.beans);
coffeeShop.buyDrink("latte");
console.log("latte, " + coffeeShop.beans);

我有此错误信息

：
“未捕获的ReferenceError：未定义makeDrink”，
你可以帮我吗？
谢谢，
问候

最佳答案

您需要引用调用上下文-this，它引用正在调用当前函数的对象的coffeeShop，该对象具有makeDrink和drinkRequirements属性。它们不是独立的函数/对象-它们是另一个对象的属性。

var coffeeShop = {
  beans: 40,
  money: 100,
  beanCost: 2,

  drinkRequirements: {
    latte: {
      beansRequirements: 10,
      price: 5
    },
    americano: {
      beansRequirements: 5,
      price: 2.5
    },
    doubleShot: {
      beansRequirements: 15,
      price: 7.5
    },
    frenchPress: {
      beansRequirements: 12,
      price: 6
    }
  },


  buySupplies: function(numBeansBought) {
    if (this.money - (numBeansBought * this.beanCost) >= 0) {
      this.money -= numBeansBought * this.beanCost;
      this.beans += numBeansBought;
    }
  },


  makeDrink: function(drinkType) {
      /*
      How to check if value exists in an object
      Let's consider an example which would answer this question
      var priceOfFood = { pizza: 14, burger 10 }
      priceOfFood.hasOwnProperty('pizza') // true
      priceOfFood['pizza'] // 14
      priceOfFood.hasOwnProperty('chips') // false
      priceOfFood['chips'] // undefined

      */
      //if (this.drinkRequirements.hasOwnProperty(drinkType) === false)
      if (!this.drinkRequirements[drinkType]) {
        alert("Sorry, we don't make " + drinkType);
        return false;
      } else {
        var beansRest = 0;
        beansRest = this.beans - this.drinkRequirements[drinkType].beansRequirements;
        if (beansRest < 0) {
          alert("Sorry, we're all out of beans!");
          return false;
        } else {
          this.beans = beansRest;
          return true;
        }
      }
    }

    ,
  buyDrink: function(drinkType) {
    if (this.makeDrink(drinkType)) {
      this.money += this.drinkRequirements[drinkType].price;
      console.log('the new coffeeShop money is ' + this.money);
    }
  }

}

coffeeShop.makeDrink("latte");
console.log("latte, " + coffeeShop.beans);
coffeeShop.buyDrink("latte");
console.log("latte, " + coffeeShop.beans);

关于javascript - 未捕获的ReferenceError:未定义makeDrink，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/49937248/