typescript - 打字稿中的递归对象映射器类型

Question

我正在 typescript 中创建一个类型安全的对象映射器。

我可以通过这个操场和这段代码让这个工作在一个更深的层次上工作

enum TransformerActions { 
  Delete = 'delete',
}

type TransformerMap<S> = { 
  [P in keyof S]?: S[P] extends object
    ? ((s: S) => any) | TransformerActions
  : S[P];
};

interface Name { 
  forename?: string;
  surname?: string;
}

type Person = { currentName: Name, previousNames: Name[] }

const personTransformer1: TransformerMap<Person> = {
  currentName: TransformerActions.Delete
}

const personTransformer2: TransformerMap<Person> = {
  currentName: (s) => s.currentName.forename + ' ' + s.currentName.surname
}

但是，如果我想让它成为递归类型，以便每个嵌套键都可以进行转换，我无法获得语法，尝试过这个：

type TransformerMap<S> = { 
  [P in keyof S]?: S[P] extends object
    ? TransformerMap<S[P]>
  : S[P] | ((s: S) => any) | TransformerActions;
};

但这不起作用。

我怎样才能以这种方式创建递归类型。

标签： typescript

Answer 1

如果我理解正确，那么这样的事情呢？

enum TransformerActions {
  Delete = 'delete',
}

type TransformerFunc<T> = (src: T) => Partial<T>

type TransformerMap<S> = {
  [P in keyof S]?: S[P] | TransformerFunc<S[P]> | TransformerActions | TransformerMap<S[P]>;
};

interface Name {
  forename?: string;
  surname?: string;
}

type Person = { currentName: Name, previousNames: Name[], child: Person }

const personTransformer1: TransformerMap<Person> = {
  currentName: TransformerActions.Delete
}

const personTransformer2: TransformerMap<Person> = {
  currentName: {
    forename: TransformerActions.Delete
  },
  child: {
    currentName: (child) => {
      return {
        forename: `${child.forename?.toUpperCase()} ${child.surname?.toUpperCase}`,
        surname: TransformerActions.Delete
      }
    },
    child: TransformerActions.Delete
  }
}

查看操场示例。