Javascript 如何注释作为对象属性的函数？

我有以下类型别名：

type TestType = {
  critical: string,
  failProps: Object,
  successProps: ?Object,
  test: Function,
};

我想说得更具体一些。该功能应具有以下特征：

function (value: string): boolean { /* ... */ }

---

如何指示测试应采用单个字符串参数并返回布尔值？

您可以使用以下语法：

type TestType = {
  critical: string,
  failProps: Object,
  successProps: ?Object,
  test: (value: string) => boolean,
};

…或者如果要在其他地方重用函数类型：

type functionType = (value: string) => boolean
type TestType = {
  critical: string,
  failProps: Object,
  successProps: ?Object,
  test: functionType,
};

---

您可以使用以下语法：

type TestType = {
  critical: string,
  failProps: Object,
  successProps: ?Object,
  test: (value: string) => boolean,
};

…或者如果要在其他地方重用函数类型：

type functionType = (value: string) => boolean
type TestType = {
  critical: string,
  failProps: Object,
  successProps: ?Object,
  test: functionType,
};