Hey @pikax , you have done a great job 👍, it looks simpler than expected, do we need to add some dts test cases for mixins/extends?

do we need to add some dts test cases for mixins/extends?

Not sure, because it will ignore all the mixins/extends the reason is, as soon as we extract the $props: insfer P we loose the Clearable and ValueType generics:

playground

declare function expectType<T>(a: T): void;

type OnChange<ValueType, Clearable> = Clearable extends true
    ? (value: ValueType | null) => void
    : (value: ValueType) => void
interface GenericProp<Clearable, ValueType> {
    clearable?: Clearable
    value?: ValueType
    onChange?: OnChange<ValueType, Clearable>
}


declare function S<
    Clearable extends boolean,
    ValueType extends string | number | null | undefined
>(): {
    $props: GenericProp<Clearable, ValueType>
}

S().$props // $props is not `GenericProp<Clearable, ValueType>`

class C<
    Clearable extends boolean,
    ValueType extends string | number | null | undefined
    > {
    $props = {} as GenericProp<Clearable, ValueType>
}

new C().$props // $props is not `GenericProp<Clearable, ValueType>`

// but `C` has the correct type


// This would also work
type VueProps<T extends new () => { $props: any }> = T
declare const Comp: VueProps<{
    new <
        Clearable extends boolean,
        ValueType extends string | number | null | undefined
        >(): { $props: GenericProp<Clearable, ValueType> }
}>

The templated constructor intact to keep the correct GenericProp<Clearable, ValueType>, which is lost when you construct or extract the $props

I would say this is an advanced usage, with the current implementation it won't support props declared on mixins/extends since to merge those you will need to extract $props which will lose the generic template.

Public API typing would also been lost, since the constructor will only return {$props}, I think the only way is to support class API component (which I started with), but with just setup method (to keep it simple), since the supporting options in Class we already have vue-class-component.

I would say this is an advanced usage, with the current implementation it won't support props declared on mixins/extends since to merge those you will need to extract $props which will lose the generic template.

I agree with this point

Must we create a new class for props definition?