类型错误：无法读取 React 中未定义的属性“map”

Question

我收到错误TypeError: Cannot read property 'map' of undefined 。 好吧，我有数组对象，我正在提取对象键，但是当我映射一个函数时，它会给我错误，有人可以帮助我如何解决我的问题。 我试过了，但我失败了，我需要解决这个应用程序。

代码

 const patientTabOptions = {
    titleOptions: [
      { value: "mr", label: "Mr" },
      { value: "ms", label: "Ms" },
      { value: "doctor", label: "Doctor" }
    ],
    ageGroup: [
      { value: "infant", label: "Infant" },
      { value: "child", label: "Child" },
      { value: "adult", label: "Adult" }
    ],
    GenderOptions: [
      { value: "male", label: "Male" },
      { value: "female", label: "Female" },
      { value: "others", label: "Others" }
    ],
    bloodGroup: [
      { value: "a+", label: "A+" },
      { value: "a-", label: "A-" },
      { value: "b+", label: "B+" },
      { value: "b+", label: "B+" },
      { value: "b-", label: "B-" },
      { value: "o", label: "O" },
      { value: "o-", label: "O-" },
      { value: "ab+", label: "AB+" },
      { value: "ab-", label: "AB-" }
    ],
    maritalStatus: [
      { value: "single", label: "Single" },
      { value: "married", label: "Married" },
      { value: "notDisclosed", label: "Not Disclosed" }
    ]
  };

 let patientKeys = Object.keys(patientTabOptions);

在渲染函数中，当我尝试映射它时给我错误

 patientTabOptions &&
                    patientTabOptions.patientKeys.map((item) =>
                      console.log(item)
                    )

Answer 1

这是因为关键的patientKeys不存在于您的patientTabOptions对象中。

如果您想遍历对象的键，则必须使用您创建的名为patientKeys的变量

patientTabOptions && patientKeys.map((item) => console.log(item))

从评论编辑：

patientTabOptions && Object.keys(patientTabOptions).map(key => patientTabOptions[key])

但是如果你想从特定数组中获取数据，你应该直接访问

const data = patientTabOptions.ageGroup