如何使用预定义的 object 键入 typescript 接口属性？

Question

• 我有一个名为 Customer 的 typescript 接口。
• 我希望该接口的一个属性 orderAuthorizationStatus 只是三个字符串之一：'unauthorized'、'waitingForAuthorization' 或 'authorized'
• 同时我想将这三个字符串存储在某个地方，这样我就可以将它们用于比较、翻译等，而不是在我决定更改措辞时更改它们 10 次不同的时间。
• 我想使用存储的字符串来输入我的界面属性，我目前有这个解决方案：

export const OrderAuthorizationStates = {
  unauthorized: "unauthorized",
  waitingForAuthorization: "waitingForAuthorization",
  authorized: "authorized"
}

export interface Customer {
  id: number;
  name: string;
  orderAuthorizationStatus: "unauthorized" | "waitingForAuthorization" | "authorized"
}

这有效并给了我我想要的错误：

let customer: Customer;

if (customer.orderAuthorizationStatus === 'asdf') {
 somecode
}

错误：“此条件将始终返回‘false’，因为类型‘‘unauthorized’ |‘waitingForAuthorization’ |‘authorized’’和‘‘asdf’’没有重叠”
我也可以这样使用它：

let customer: Customer;

if (customer.orderAuthorizationStatus === OrderAuthorizationStates.authorized) {
 somecode
}

我无法解决的是，如何使用我的 OrderAuthorizationStates object 的对象属性来键入我的客户界面的接口属性：

export interface Customer {
  id: number;
  name: string;
  orderAuthorizationStatus: OrderAuthorizationStates.unauthorized | OrderAuthorizationStates.waitingforAuthorization | OrderAuthorizationStates.authorized
}

错误：找不到命名空间“OrderAuthorizationStates”

帮助将不胜感激！

Answer 1

字符串枚举几乎完全符合您的要求：

enum OrderAuthorizationStates {
    Unauthorized = "Unauthorized",
    WaitingForAuthorization = "WaitingForAuthorization",
    Authorized = "Authorized"
}

interface Customer {
    id: number;
    name: string;
    orderAuthorizationStatus: OrderAuthorizationStates;
}

let customer: Customer = { id: 1, name: "RichN", orderAuthorizationStatus: OrderAuthorizationStates.Unauthorized};
if (customer.orderAuthorizationStatus === "Unauthorized") {
    console.log("Customer is unauthorized");
}

// Authorize it!
customer.orderAuthorizationStatus = OrderAuthorizationStates.Authorized;

if (customer.orderAuthorizationStatus === OrderAuthorizationStates.Authorized) {
    console.log("Customer is now authorized");
}

// Output:
// Customer is unauthorized
// Customer is now authorized

此外，如果你这样做if (customer.orderAuthorizationStatus === 'asdf')你会得到错误'This condition will always return 'false' since the types 'OrderAuthorizationStates' and '"asdf"' have no overlap.'，其中是你想要的。

Answer 2

找到了一种不使用枚举的方法。

创建一个从 object 推断出的类型：

export const OrderAuthorizationStatuses = {
    unauthorized: 'unauthorized',
    waitingForAuthorization: 'waitingForAuthorization',
    authorized: 'authorized'
}

type OrderAuthorizationStatus = typeof OrderAuthorizationStatuses[keyof typeof OrderAuthorizationStatuses]

现在，您可以在整个应用程序中使用 object 键作为变量，而不会对 enum.member 有任何类型误解，您可以在其上使用所有 object 方法，此外，您还可以使用它来键入接口属性或任何其他内容：

export interface Customer {
  id: number;
  name: string;
  orderAuthorizationStatus: OrderAuthorizationStatus
}

来源