联合类型的部分键作为打字稿中对象的键 [英] Partial keys of union type as key of an object in typescript

问题描述

我想在打字稿中使用联合类型的键作为对象的键.

I want to use the keys of the union type as key of the object in typescript.

type EnumType = 'a1' | 'a2'

const object:{[key in EnumType]: string}= {
 a1: 'test'
}

在这种情况下，我甚至必须添加 a2 作为对象中的键.有没有办法让它成为可选的?

In this case I have to add even a2 as a key in the object. Is there a way to make this optional?

推荐答案

只需像这样添加一个问号:

Just add a question mark like this:

type EnumType = 'a1' | 'a2'

const object:{[key in EnumType]?: string}= {
 a1: 'test'
}

object 定义与您当前的代码:

The object definition with your current code:

const object: {
    a1: string | undefined;
    a2: string | undefined;
}

变成:

const object: {
    a1?: string | undefined;
    a2?: string | undefined;
}

允许每个键都是可选的.

Allowing every key to be optional.

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