多维数组 利用递归 修改key

    formatFr(fr) {
      let $arr = [];
      let obj = {};
      fr.forEach(item => {
        let tmp = { ...item };
        if (tmp.children) {
          tmp.children = this.formatFr(tmp.children);
          obj = {
            value: tmp.id,
            label: tmp.value,
            children: tmp.children
          };
        }else{
          obj = {
            value: tmp.id,
            label: tmp.value
          };
        }
        $arr.push(obj);
      });
      return $arr;
    },