[英]How to create enum values as type/interface in typescript?
I have enum:我有枚举:
enum DemoEnum {
a = 'EnumValueA',
b = 'EnumValueB'
}
I would like to create type Type = 'EnumValueA' | 'EnumValueB'
我想创建
type Type = 'EnumValueA' | 'EnumValueB'
type Type = 'EnumValueA' | 'EnumValueB'
from my enum values. type Type = 'EnumValueA' | 'EnumValueB'
来自我的枚举值。
How can I do this?我怎样才能做到这一点?
My current state is type of "keys":我目前的状态是“钥匙”类型:
type Type = keyof typeof DemoEnum // 'a' | 'b'
For example I would like to use it in my react props.例如,我想在我的反应道具中使用它。
type Props {
value: 'EnumValueA' | 'EnumValueB',
}
In case of usage <MyComponent value='EnumValueA'>
如果使用
<MyComponent value='EnumValueA'>
type Props {
value: DemoEnum,
}
I am getting an error Type .. is not assignable to DemoEnum
我收到一个错误
Type .. is not assignable to DemoEnum
Generally enum
s are meant to shield users from having to care about their particular values.通常
enum
旨在保护用户不必关心他们的特定值。 In some sense you should be able to change the actual string/number values and not change the rest of your code.从某种意义上说,您应该能够更改实际的字符串/数字值,而不是更改代码的其余部分。 The conventional way to use this in your react component would therefore look like:
因此,在您的 React 组件中使用它的传统方法如下所示:
type Props = {
value: DemoEnum
}
<MyComponent value={DemoEnum.a} />
which should compile without error.应该编译没有错误。
On the flip side, if you find yourself caring a lot about the actual string values "EnumValueA"
and "EnumValueB"
, you might consider abandoning enum
s entirely and just make a plain object for it:另一方面,如果您发现自己非常关心实际的字符串值
"EnumValueA"
和"EnumValueB"
,您可能会考虑完全放弃enum
并为其创建一个普通对象:
const DemoEnum = {
a: 'EnumValueA',
b: 'EnumValueB'
} as const;
and synthesize the types you care about by inspecting it:并通过检查来综合您关心的类型:
type DemoEnumObject = typeof DemoEnum;
type DemoEnum = DemoEnumObject[keyof DemoEnumObject];
type Props = {
value: DemoEnum
}
which then will work as然后将作为
<MyComponent value="EnumValueA" />
or as或作为
<MyComponent value={DemoEnum.a} />
Template Literal Types 发布后,你可以直接使用它来得到你想要的:
type Enum = `${DemoEnum}` // "EnumValueA" | "EnumValueB"
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