getOutData() {
// searchCategoryBySpecialId 调用的外层数据接口
      searchCategoryBySpecialId({specialId: this.id}, data => {
        if(data.categoryPOList && data.categoryPOList.length) {
          let arr = []
          data.categoryPOList.forEach(async(item,index) => {
            let obj = {}
            obj.title = item.typeName
            obj.id = item.id
            obj.list = await this.getInData(item.id)
            arr.push(obj)
          })
          this.datalist = arr // datalist 为最终所需要的数据
        }
      })
    },

getInData(categoryId) {
      let params = {
        specialId: this.id,
        categoryId
      }
// 使用promise将数据返回
      const promise = new Promise((resolve,reject) => {
        ajaxSearchSpecialCourseListByCategoryId(
          params, 
          data => {
            resolve(data.list || [])
          },
          errorMsg => {
            reject(errorMsg)
          },
          false
        )
      })
      return promise
    },

所得到的数据形式如下：