使用axios访问json文件，能得到json返回的结果，但是为啥访问不到这个返回的结果里面的data对象了

vue代码：
....省略其他代码

methods:{
        getHomeInfo(){
            axios.get('/api/index.json')
                .then(this.getHomeInfoSucc)
        },
        getHomeInfoSucc(res){
            console.log(res);
            res =res.data
            console.log(res);
            console.log(res.ret);//undefined =>???
            console.log(res.data);//undefined =>???
            if (res.ret && res.data) {
                const data = res.data
                this.iconList=data.iconList
            }
        }
    },
    mounted(){
        this.getHomeInfo()
    }

....省略其他代码

json文件：

{
  "ret":true,
  "data":{
      "iconList":[
        {
          "id":1,
          "imgUrl":"https://gw.alicdn.com/tps/TB1d30fPVXXXXbGXXXXXXXXXXXX-183-144.png_.webp",
          "desc":"天猫优选"
        },{
          "id":2,
          "imgUrl":"https://gw.alicdn.com/tfs/TB1lZyXcQyWBuNjy0FpXXassXXa-183-144.png?getAvatar=1_.webp",
          "desc":"聚划算"
        },{
          "id":3,
          "imgUrl":"https://gw.alicdn.com/tfs/TB163FbPVXXXXcKXXXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"天猫国际"
        },{
          "id":4,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"外卖"
        },{
          "id":5,
          "imgUrl":"https://gw.alicdn.com/tfs/TB1PDDqetzJ8KJjSspkXXbF7VXa-183-144.png_.webp",
          "desc":"超市"
        },{
          "id":6,
          "imgUrl":"https://gw.alicdn.com/tfs/TB1282DexGYBuNjy0FnXXX5lpXa-183-144.png_.webp",
          "desc":"手机充值"
        },{
          "id":7,
          "imgUrl":"https://gw.alicdn.com/tfs/TB19RMHvqmWBuNjy1XaXXXCbXXa-183-144.png?getAvatar=1_.webp",
          "desc":"猪猪旅行"
        },{
          "id":8,
          "imgUrl":"https://gw.alicdn.com/tfs/TB18leuChGYBuNjy0FnXXX5lpXa-183-144.png?getAvatar=1_.webp",
          "desc":"领金币"
        },{
          "id":9,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"拍卖"
        },{
          "id":10,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"一日游"
        },{
          "id":11,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"必玩"
        },{
          "id":12,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"梅岭"
        },{
          "id":13,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"汽车票"
        },{
          "id":14,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"本地游玩"
        },{
          "id":15,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"游乐场"
        },{
          "id":16,
          "imgUrl":"https://gw.alicdn.com/tps/TB1eXc7PFXXXXb4XpXXXXXXXXXX-183-144.png?getAvatar=1_.webp",
          "desc":"万达乐园"
        }],

....省略其他代码

就是当我打印

console.log(res.ret);//undefined =>???，
console.log(res.data);//undefined =>???，

为啥我这里会打印出 undefined，各位大神帮忙指点一下，谢谢大家