typescript - 实现 Typescript 类接口(interface)不保留方法类型

Question

我正在尝试编写一个 Typescript 接口(interface)，然后编写一个实现该接口(interface)的类。

问题是我似乎无法从接口(interface)获取方法签名以应用于类。

这是一个精简的示例:

export interface Foo {
  bar(value: string): void;
}


export class MyFoo implements Foo {
  // ✔️ Typescript error:
  // Property 'bar' is missing in type 'MyFoo' but required in type 'Foo'
}


export class MyFoo implements Foo {
  // value is inferred as `any` instead of `string`, 
  // and there aren't any errors with the return type mismatch
  bar(value) { return true; }
}

似乎编译器知道 bar方法应该存在，但由于某种原因不保留它的签名。

Answer 1

t seems that the compiler is aware that the bar method should exist, but doesn't preserve the signature of it for some reason.

正确的。原因如下: https://github.com/Microsoft/TypeScript/pull/6118#issuecomment-216595207

因此，开发人员有责任添加他们需要的注释。