如何让 Typescript 从通用类型列表中的 Array.map 调用推断特定类型？

Question

以下代码有效：

interface Model {
  keyFromModel: string;
  anotherKeyFromModel: number;
}
export const getKeyLoader = <T, K extends keyof T>(model: mongoose.Model<T & mongoose.Document>, key: K, one: boolean) => {
  type inputType = NonNullable<T[K]>; // this becomes type "string"
}

我可以这样称呼它

getKeyLoader(model, "keyFromModel", true).load()

...并且 K 的类型是“keyFromModel”。

但是我希望加载器参数接受来自 model 接口的键数组。

export const getLoadersForModel = <T, K extends keyof T>(model: mongoose.Model<T & mongoose.Document>, loaders: K[]) => {
  const dataLoaders = loaders.map((key) => { // key is inferred as keyof T
      const test = getKeyLoader(model, key, true);
      return test;
  });
}
/// ... in getKeyLoader ...
// type inputType = NonNullable<T[K]>; // K becomes a union of all `keyof T ` and inputType becomes `any`

而是将keyof Model类型的完整联合集传递给getKeyLoader ，而我只想要Array.map调用和字符串文字类型的迭代中的密钥。

Answer 1

显然我有另一个包装器 function 我忘了：

<T>(name: string, types: string, loaders: (keyof T)[]) => {
  ...getKeyLoader(...)
}

我将其更改为此以解决问题：

<T, K extends keyof T>(name: string, types: string, loaders: K[])