用axios提取出本地的json文件，格式如下
  
  "Merch": {
"hamburger": {
  "1": {
    "goodsImg": "http://7xjyw1.com1.z0.glb.clouddn.com/pos001.jpg",
    "goodsName": "香辣雞腿堡",
    "price": 18
  },
  "2": {
    "goodsImg": "http://7xjyw1.com1.z0.glb.clouddn.com/pos002.jpg",
    "goodsName": "田園雞腿堡",
    "price": 15
  }
},
"friedChicken": {
  "3": {
    "goodsImg": "http://7xjyw1.com1.z0.glb.clouddn.com/pos003.jpg",
    "goodsName": "大包薯條",
    "price": 18
  },
  "4": {
    "goodsImg": "http://7xjyw1.com1.z0.glb.clouddn.com/pos002.jpg",
    "goodsName": "脆皮炸雞腿",
    "price": 20
  }
｝



axios
  .get("/static/data/Merch.json")
  .then(response => {
    let Merchs = response.data.Merch;
    for (let key in Merchs) {
      let eph = Merchs[key];
      this.typeMerch.key=eph;
    }        
  })
  
  console.log(key),打印出來的是hamburger和frideChicken；
  但是下面想添加進屬性里，key卻變成了字符串
  為什么啊
  有大大可以解釋一下嗎