[英]Typescript how to infer type from class constructor arguments
I have a class definition that has typed arguments on the constructor.我有一个 class 定义,它在构造函数上输入了 arguments 。 I want to reuse the argument type definition elsewhere without refactoring or extracting the definition from the class.
我想在其他地方重用参数类型定义,而不重构或从 class 中提取定义。 How can I do this.
我怎样才能做到这一点。 below is an example with a
GetProps<TBase>
type that I was suggested but doesn't actually work.下面是我建议但实际上不起作用的
GetProps<TBase>
类型的示例。 I expect the const bp
definition to throw an error because it is missing the derp
field which is defined in the constructor.我希望
const bp
定义会引发错误,因为它缺少构造函数中定义的derp
字段。
type GetProps<TBase> = TBase extends new (props: infer P) => any ? P : never
class Bro {
bro: string = 'cool'
cool: string = 'lol'
constructor(props: {bro: string, cool: string, derp: string}){
this.bro = props.bro;
this.cool = props.cool;
}
}
const bp : GetProps<Bro> = {
bro: 'lol',
cool: 'wut'
};
TypeScript includes a utility type for this: ConstructorParameters<Type>
TypeScript 为此包括一个实用程序类型:
ConstructorParameters<Type>
const bp: ConstructorParameters<typeof Bro>[0] = {
/* ^^
Property 'derp' is missing in type '{ bro: string; cool: string; }'
but required in type '{ bro: string; cool: string; derp: string; }'.(2741) */
bro: 'lol',
cool: 'wut'
};
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