vue.js created:function(){}里面可以写函数吗

想通过methods 里的点击事件改变creat页面的渲染。

created:function(){
            function classfy(index){
                switch(index){
                    case 0:dishes = this.bigDishes.recommend;
                    break;
                    case 1:dishes = this.bigDishes.specile;
                    break;
                    case 2:dishes = this.bigDishes.chinesemeal;
                    break;
                }
            }
            console.log(dishes);
        },

methods:{
            chooesMenu:function(index,event){
                this.Index=index;
                this.menuTitle = event.currentTarget.innerText;
                classfy(index);
            },

意思是通过点击事件的index的变化改变页面的渲染。
data里面bigDishes是这一串：

bigDishes:{"recommend":[
                {"img":"../kabuqinuo.jpg","name":"卡布奇诺","saleNum":"219","price":"29","num":"1"},
                {"img":"../kabuqinuo.jpg","name":"毅志咖啡","saleNum":"209","price":"32","num":"1"}
            ],
            "specile":[
                {"img":"../kabuqinuo.jpg","name":"卡布奇诺","saleNum":"219","price":"29","num":"1"},
                {"img":"../kabuqinuo.jpg","name":"卡布奇诺","saleNum":"219","price":"29","num":"1"},
                {"img":"../kabuqinuo.jpg","name":"哥伦比亚咖啡","saleNum":"119","price":"28","num":"1"}
            ],
            "chinesemeal":[
                {"img":"../kabuqinuo.jpg","name":"毅志咖啡","saleNum":"209","price":"32","num":"1"}
            ]
            }

然后html里大概要实现的功能就是通过点击左边菜单栏改变右边的内容。效果图大概如下：

但是我这样做之后报错了：

麻烦路过的大神帮忙指点，不胜感激！

没有定义 let dishes = ''

那就不要写在 create里面
写在
methods:{
chooesMenu:function(index,event){
this.Index=index;
this.menuTitle = event.currentTarget.innerText;
this.classfy(index);
},
classfy(index) {
switch(index){
case 0: this.dishes = this.bigDishes.recommend;
break;
case 1:this.dishes = this.bigDishes.specile;
break;
case 2:this.dishes = this.bigDishes.chinesemeal;
break;
}
}