我有一个简单的vue.js应用程序，我正在尝试使用typescript打印一些文本。JSON响应如下：
{
   "data": [
      {
         "firstName": "Foo",
         "lastName": "Smith"
      },
      {
         "firstName": "Mike",
         "lastName": "vue"
      },
      {
         "firstName": "go",
         "lastName": "lang"
      }
   ],
   "metadata": "none"
}
typescript
export interface TestResponse {
   firstName: string;
   lastName: string;
}
axios调用
const request: AxiosInstance = axios.create({
   baseURL: url.baseUrl,
   headers: {
      'content-type': 'application/json',
   },
   //params: {base64_encoded: 'true', fields: 'stdout'},
});
export const api = {
   async getTest() {
      try{
         return await request.get<TestResponse[]>("/v1/test")
            .then(res => {
               console.log("lastname " + res.data[0].lastName);
               return res.data
            })
      }catch (err) {
         console.log("error" + err);
      }
   },
}
但是在这里它总是渲染为undefined。我尝试了TestResponse[]和Array<TestResponse>但都无济于事。
这应该给我一个数组，但我得到了
无法读取undefined的属性（读取'data'）
export default {
   name: "Test",
   setup() {
      const firstName = ref('');
      const lastName = ref('');
      const submit = async () => {
         try {
            const response = await api.getTest()
            if (response != null) {
               firstName.value = response[0].firstName
               lastName.value = response[0].lastName
               console.log("I am a name " + response[0].lastName)
            }
         } catch (error) {
            console.log('获取响应时出错：', error)
         }
      }
      return {
         firstName,
         lastName,
         submit
      }
   },
};

export interface TestResponse {
  firstName: string
  lastName: string
}
export interface TestResponseRO {
  data: TestResponse[]
  metadata: string
}

async getTest() {
  try {
    const res = await request.get<TestResponseRO>("/v1/test");
    console.log(res.data) // Should display '{ "data": [your array], "metadata": "none"}'
    return res.data 
  } catch (err) {
    console.error(err)
  }
}