[英]Inferring Nested Generic Parameter and Returning It from Function
I have an IModelDefinition
like this: 我有一个这样的
IModelDefinition
:
export interface IModelDefinition<MT extends Typegoose, QT> {
model: new () => MT;
}
QT isn't directly used in the interface itself, but it is passed as a helper to other functions, like this so Typescript can infer the QT automatically: QT并不是直接在界面本身中使用的,而是作为辅助函数传递给其他功能的,因此Typescript可以自动推断QT:
public async getSingleMatch<MT extends Typegoose, QT>(
definition: ModelDefinition<MT, QT>,
doc: QT
): Promise<MT> ...
And I call the function like this: 我这样调用该函数:
// Account is a ModelDefinition<AccountClass, {identifier: string} and
// if I remove the identifier string, it gives an error as I expect it to.
const account = await getSingleMatch(Account, {
identifier: params.identifier,
});
Everything is right until getting the result. 一切正常,直到得到结果。 The result is type of
Typegoose
, but it should be of type AccountClass
instead. 结果为
Typegoose
类型,但应改为AccountClass
类型。 How can I solve this? 我该如何解决? Thanks for your help.
谢谢你的帮助。
EDIT: To resolve misunderstanding; 编辑:解决误会; I can pass the types, but the whole reason I'm building this is to not to pass the types and make it infer automatically.
我可以传递类型,但是构建此文件的全部原因是不传递类型并使其自动推断。 Isn't there a way?
没办法吗?
I think you should also pass the type while calling the function. 我认为您在调用函数时也应该传递类型。
const account = await getSingleMatch<AccountClass, {identifier: string}>(Account, {identifier: params.identifier})
Now if you don't want the type to be passed every time you call the function and want it to infer the AccountClass
, so just assign the default type AccountClass
to the generic type. 现在,如果您不想在每次调用该函数时都希望传递该类型,并希望其推断
AccountClass
,那么只需将默认类型AccountClass
分配给泛型类型。
public async getSingleMatch<MT extends Typegoose = AccountClass, QT>(
definition: ModelDefinition<MT, QT>,
doc: QT
): Promise<MT> ...
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