接口获取数据oldArr

[
  {
    "deptCode": "01",
    "parentCode": "000",
    "sortKey": 4,
    "deptName": "办公室（党委办公室、董事会办公室）",
    "children": [
      {
        "deptCode": "0101a",
        "parentCode": "01",
        "sortKey": 999,
        "deptName": "董事监事"
      },
      {
        "deptCode": "0104",
        "parentCode": "01",
        "sortKey": 999,
        "deptName": "总部"
      },
      {
        "deptCode": "0100",
        "parentCode": "01",
        "sortKey": 999,
        "deptName": "公司领导"
      },
      {
        "deptCode": "0107",
        "parentCode": "01",
        "sortKey": 999,
        "deptName": "汽车队"
      }
    ]
  }
]

处理后的数据newArr

[
    {
        "label": "全部部门",
        "value": "0"
    },
    {
        "label": "办公室（党委办公室、董事会办公室）",
        "value": "01",
        "children": [
            {
                "label": "全部部门",
                "value": "0"
            },
            {
                "label": "董事监事",
                "value": "0101a"
            },
            {
                "label": "总部",
                "value": "0104"
            },
            {
                "label": "公司领导",
                "value": "0100"
            },
            {
                "label": "汽车队",
                "value": "0107"
            }
        ]
    }
]

处理方法formaterDe

this.newArr = this.formaterDe(this.oldArr)

  formaterDe(arr = [], key = 'deptName', keys = 'deptCode') {
      return [{ label: key == 'deptName' ? "全部部门" : '全部员工', value: "0" }, ...(arr.map(a => {
        let obj = {};
        obj.label = a[key];
        obj.value = `${a[keys]}`;
        if (a.children) obj.children = this.formaterDe(a.children);
        return obj;
      }))];
    },

效果图