如何创建需要设置单个属性的Partial-like [英] How to create a Partial-like that requires a single property to be set

问题描述

我们的结构如下：

 出口类型LinkRestSource = {
 model：string; 
 rel ?: string; 
 title？：string; 
} | {
 model？：string; 
 rel：string; 
 title？：string; 
} | {
 model？：string; 
 rel ?: string; 
 title：string; 
}; 
  

这与说法几乎相同

  type LinkRestSource =部分< {model：string，rel：string，title：string}> 
  

除了这将允许空对象被传入，而初始类型需要其中一个属性在

中传递如何创建类似于部分的泛型，但其行为与上面的结构相似？

解决方案

我想我有一个适合您的解决方案。您正在寻找一些类型为 T 的东西，并生成一个相关类型，其中至少包含 属性< T 。也就是说，它就像部分< T> ，但不包括空对象。

如果是这样，这里是：

  type AtLeastOne   

解析它：首先， AtLeastOne< T> 为部分< T> 与 相交。 U [keyof U] 表示它是 U 的所有属性值的联合。我已经定义（默认值） U 为映射类型，其中 T 的每个属性映射到 Pick< T ，K> ，这是键 K 的单一属性类型。 （例如， Pick< {foo：string，bar：number}，'foo'> 相当于 {foo：string} ...它从原始类型中挑选'foo'属性。）含义 U [keyof U] 在这种情况下是来自 T 的所有可能的单一财产类型的联合。

嗯，这可能会让人困惑。让我们一步步看看它是如何在以下具体类型上运行的：

 类型FullLinkRestSource = {
 model：串; 
 rel：string; 
 title：string; 
} 
 
 type LinkRestSource = AtLeastOne< FullLinkRestSource> 
  

扩展为

  type LinkRestSource = AtLeastOne< FullLinkRestSource，{
 [Key in FullFRestSource]中的K：Pick< FullLinkRestSource，K> 
}> 
  

或

  type LinkRestSource = AtLeastOne< FullLinkRestSource，{
 model：Pick< FullLinkRestSource，'model'> ;, 
 rel：Pick< FullLinkRestSource，'rel'> ;, 
 title：选择< FullLinkRestSource，'标题'> 
}> 
  

或

  type LinkRestSource = AtLeastOne< FullLinkRestSource，{
 model：{model：string}，
 rel：{rel：string}，
 title：{title：string}> 
}> 
  

或

  type LinkRestSource =部分< FullLinkRestSource> &安培; {
模型：{model：string}，
 rel：{rel：string}，
 title：{title：string}> 
} [keyof {
 model：{model：string}，
 rel：{rel：string}，
 title：{title：string}> 
}] 
  

或

  type LinkRestSource =部分< FullLinkRestSource> &安培; {
模型：{model：string}，
 rel：{rel：string}，
 title：{title：string}> 
} ['model'| 'rel'| 'title'] 
  

或

  type LinkRestSource =部分< FullLinkRestSource> &安培; 
（{model：string} | {rel：string} | {title：string}）
  

或

  type LinkRestSource = {model ?: string，rel ?: string，title ?: string}& 
（{model：string} | {rel：string} | {title：string}）
  

或

  type LinkRestSource = {model：string，rel ?: string，title ?: string} 
 | {model？：string，rel：string，title？：string} 
 | {model？：string，rel？：string，title：string} 
  

你可以测试它：

  const okay0：LinkRestSource = {model：'a'，rel：'b'，title：'c'} 
 const okay1：LinkRestSource = {model：'a'，rel：'b'} 
 const okay2：LinkRestSource = {model：'a'} 
 const okay3：LinkRestSource = {rel：'b'} 
 const okay4：LinkRestSource = {title：'c'} 
 
 const error0：LinkRestSource = {//缺少属性
 const错误1：LinkRestSource = {model：'a'，titel：'c'} //字符串文字的额外属性
  

那么，这对你有用吗？祝你好运！

We have structure that is like the following:

export type LinkRestSource = {
    model: string;
    rel?: string;
    title?: string;
} | {
    model?: string;
    rel: string;
    title?: string;
} | {
    model?: string;
    rel?: string;
    title: string;
};

Which is almost the same as saying

type LinkRestSource = Partial<{model: string, rel: string, title: string}>

Except that this will allow an empty object to be passed in whereas the initial type requires one of the properties to be passed in

How can I create a generic like Partial, but that behaves like my structure above?

解决方案

I think I have a solution for you. You're looking for something that takes a type T and produces a related type which contains at least one property from T. That is, it's like Partial<T> but excludes the empty object.

If so, here it is:

type AtLeastOne<T, U = {[K in keyof T]: Pick<T, K> }> = Partial<T> & U[keyof U]

To dissect it: first of all, AtLeastOne<T> is Partial<T> intersected with something. U[keyof U] means that it's the union of all property values of U. And I've defined (the default value of) U to be a mapped type where each property of T is mapped to Pick<T, K>, a single-property type for the key K. (For example, Pick<{foo: string, bar: number},'foo'> is equivalent to {foo: string}... it "picks" the 'foo' property from the original type.) Meaning that U[keyof U] in this case is the union of all possible single-property types from T.

Hmm, that might be confusing. Let's see step-by-step how it operates on the following concrete type:

type FullLinkRestSource = {
  model: string;
  rel: string;
  title: string;
}

type LinkRestSource = AtLeastOne<FullLinkRestSource>

That expands to

type LinkRestSource = AtLeastOne<FullLinkRestSource, {
  [K in keyof FullLinkRestSource]: Pick<FullLinkRestSource, K>
}>

or

type LinkRestSource = AtLeastOne<FullLinkRestSource, {
  model: Pick<FullLinkRestSource, 'model'>,
  rel: Pick<FullLinkRestSource, 'rel'>,
  title: Pick<FullLinkRestSource, 'title'>
}>

or

type LinkRestSource = AtLeastOne<FullLinkRestSource, {
  model: {model: string},
  rel: {rel: string},
  title: {title: string}>
}>

or

type LinkRestSource = Partial<FullLinkRestSource> & {
  model: {model: string},
  rel: {rel: string},
  title: {title: string}>
}[keyof {
  model: {model: string},
  rel: {rel: string},
  title: {title: string}>
}]

or

type LinkRestSource = Partial<FullLinkRestSource> & {
  model: {model: string},
  rel: {rel: string},
  title: {title: string}>
}['model' | 'rel' | 'title']

or

type LinkRestSource = Partial<FullLinkRestSource> &
  ({model: string} | {rel: string} | {title: string})

or

type LinkRestSource = {model?: string, rel?: string, title?: string} & 
  ({model: string} | {rel: string} | {title: string})

or

type LinkRestSource = { model: string, rel?: string, title?: string } 
  | {model?: string, rel: string, title?: string} 
  | {model?: string, rel?: string, title: string}

which is, I think, what you want.

You can test it out:

const okay0: LinkRestSource = { model: 'a', rel: 'b', title: 'c' }
const okay1: LinkRestSource = { model: 'a', rel: 'b' }
const okay2: LinkRestSource = { model: 'a' }
const okay3: LinkRestSource = { rel: 'b' }
const okay4: LinkRestSource = { title: 'c' }

const error0: LinkRestSource = {} // missing property
const error1: LinkRestSource = { model: 'a', titel: 'c' } // excess property on string literal

So, does that work for you? Good luck!

这篇关于如何创建需要设置单个属性的Partial-like的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！