object获取的两种方式： 

  data() {
    return {
      abj: {
        aa: {A: '1'}
      }
    }
  },
  created() {
    console.log(this.abj.aa)    //第一种
    console.log(this.abj["aa"])    //第二种
  },

 Object.keys使用/解构赋值：

    return {
      footList: [],
      abj: {
        aa: {A: '12',AA:'22'},
        bb: {B: '1'}
      },
      ABJ:[100,200,300]
    }
  },
  created() {
    this.deepCopy()
    //Object.keys返回值是数组
    console.log(Object.keys(this.abj))    //参数为对象时 返回值是数组，存放的是对象key
    //['aa','b']
    console.log(Object.keys(this.ABJ))    //参数为数组时 返回值是数组，存放的是数组索引，和用for in遍历数组的顺序一样
    //['0','1','2']
    for (const BB in this.ABJ){
      console.log(BB)   
        //0
        //1
        //2
    }
    //对象解构赋值
    let {A} = this.abj.aa
    console.log(A)    //12
    //数组解构赋值
    let [B]= this.ABJ
    console.log(B)    //100
    //扩展运算符
    console.log(...this.ABJ)    //100 200 300   一行输出的哦
  },