如何使用枚举（作为静态变量附加到类）作为类型

【问题标题】：How to use enum (attached to a class as a static variable) as a type如何使用枚举（作为静态变量附加到类）作为类型
【发布时间】：2020-08-10 14:06:01
【问题描述】：

// file1.ts

enum Variant {
  Success = 'success',
  Error = 'error',
}

export class Example {
  static Variant = Variant;
}


// file2.ts

import { Example } from './file1';

type Props = {
  variant: Example.Variant; // TS2702: 'Example' only refers to a type, but is being used as a namespace here.
};

Typescript 抛出错误：TS2702: 'Example' only refers to a type, but is being used as a namespace here.

我知道我可以导出枚举本身并在file2.ts 中使用它，但我想知道为什么上面的示例不起作用。

【问题讨论】：

标签： javascript reactjs typescript enums

【解决方案1】：

Variant 是 static 类字段

export class Example {
  // Variant here is a class field
  static Variant = Variant;
}

因此，如果您想将 Variant 用作type 到class Example，则应在Example.Variant 之前添加typeof

import { Example } from './file1';

type Props = {
  // This statement means that Example is a namespace that contains Variant as a type or class named Variant, which in our case it is a field
  variant: Example.Variant; // wrong
  variant: typeof Example.Variant; // correct
};

所以出现错误是因为您使用class 作为namespace

【讨论】：

知道了。谢谢你:)