打字稿:传播类型只能从对象类型创建 [英] Typescript: Spread types may only be created from object types

问题描述

function foo<T extends object>(t: T): T {

  return {
    ...t // Error: [ts] Spread types may only be created from object types.
  }
}

我知道 github 上存在问题，但我无法弄清楚哪些已修复，哪些未修复，并且他们有 2695 个未解决的问题.所以我在这里发帖.我使用的是最新的 Typescript 2.9.2.

I am aware that there are issues on github, but I can't figure out what is fixed and what is not and they have 2695 open issues. So I am posting here. I am using latest Typescript 2.9.2.

上面的代码应该不行吧?如果可能，我该如何解决?

Should the above code not work? And how can I fix it if possible?

推荐答案

此问题已在 TypeScript 3.2 版中修复.请参阅发行说明.

This is fixed in TypeScript Version 3.2. See Release Notes.

看起来像泛型传播尚不支持，但有一个关于它的 GitHub 问题:微软/TypeScript#10727.

Looks like spread with a generic type isn't supported yet, but there is a GitHub issue about it: Microsoft/TypeScript#10727.

现在你可以使用 类型断言 喜欢 @Jevgeni 评论:

For now you can either use type assertion like @Jevgeni commented:

function foo<T extends object>(t: T): T {
  return { ...(t as object) } as T;
}

或者您可以使用具有正确类型定义的 Object.assign.

or you can use Object.assign which has proper type definitions.

function foo<T extends object>(t: T): T {
  return Object.assign({}, t);
}

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