Question

我正在使用类型安全的Typescript创建对象映射器。

我可以使用this playground和此代码在一个层次上深入研究

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，如果我想将其设为递归类型，以便每个嵌套键都可以进行转换，则无法获取语法，请尝试以下操作：

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。

如何以这种方式创建递归类型。

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
  }
}

签出playground example。

打字稿中的递归对象映射器类型

1 个答案: