如何从计算属性名称的函数参数中获取文字类型? [英] How to get a literal type from a function argument for a computed property name?

问题描述

请考虑以下代码:

const fn = (name: string) => {
  return { [name]: "some txt" };
};

const res = fn("books"); // books or any other string

TS 将 res 识别为以下类型:

TS recognizes res as the following type:

const res: {
  [x: string]: string;
}

我想让 TS 知道 res 有一个属性 books

I'd like TS to know that res has a property books

const res: {
  books: string;
}

我尝试了很多东西，但似乎没有任何效果.有可能吗?这是一个已知问题吗?

I tried many things but nothing seems to work. Is it possible at all? Is it a known issue?

推荐答案

你必须像这样创建一个泛型函数:

You have to create a generic function like this:

const fn = <T extends string>(name: T): { [key in T]: string } => {
  return { [name]: "some txt" } as any;
};

const res = fn("books");

这似乎是 TypeScript 中的一个错误，它不允许这样的事情，这就是为什么你需要 as any.请参阅此处交互示例

It seems like a bug in TypeScript that it doesn't allow such things, that's why you need the as any. See here for an interactive example.

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