[英]Generics: Type as property name
Is it possible with generics to pass an object for usage as not only the type, but as the key?泛型是否可以将对象不仅作为类型而且作为键传递使用?
interface store {
category: string
}
interface ajaxResponse<T> {
data: ajaxData<T>
errors: string[]
success: boolean
}
interface ajaxData<T> {
rewards: {
amount: number
error: string
}
T: T
}
function get<T>(url): Promise<ajaxResponse<T>> {
// make ajax GET request
// return json object
}
let res = await get<store>('/my/url')
res.data.store.category
When I do that, it says当我这样做时,它说
Property 'store' does not exist on type 'ajaxData'
“ajaxData”类型上不存在属性“store”
Is there a way for me to access that property?有没有办法让我访问该属性? It works once compiled since all that is removed, but how can I get it working in the editor?
自从所有内容都被删除后,它一旦编译就可以工作,但是我怎样才能让它在编辑器中工作?
Edit编辑
After thinking about it, I think I don't want the interface and the property to be the same.想了想,我想我不希望接口和属性是一样的。 I think I would want to use an
interface
with name x
, so maybe something like this:我想我想使用名称为
x
的interface
,所以可能是这样的:
let res1 = await get<storeA, 'category'>('/my/url1')
let res2 = await get<storeB, 'catList'>('/my/url2')
res1.data.category.category
res2.data.catList.categories
Yes if you have property name as explicit literal type, you can declare a type having property with that name by using mapped type syntax :是的,如果您将属性名称作为显式文字类型,则可以使用映射类型语法声明具有该名称的属性的类型:
type A<T, PropertyName extends string> = {[P in PropertyName]: T}
So the complete example should look like所以完整的例子应该看起来像
interface store {
category: string
}
interface ajaxResponse<T, PropertyName extends string> {
data: ajaxData<T, PropertyName>
errors: string[]
success: boolean
}
type ajaxData<T, PropertyName extends string> = {
rewards: {
amount: number
error: string
}
} & {[P in PropertyName]: T}
function get<T, PropertyName extends string>(url): Promise<ajaxResponse<T, PropertyName>> {
// make ajax GET request
// return json object
return null;
}
async function test() {
let res = await get<store, 'store'>('/my/url')
res.data.store.category
}
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