即使类型不匹配，打字稿也没有错误

Question

type path= {
    col(...args: any[]): string
    doc(...args: any[]): string
}

export const creator =  <
    C extends path['col'],
    D extends path['doc']
>(pathGenerator: {
    col: C
    doc: D
}) => pathGenerator

export const profile = creator({
    col({ userId }:{ userId: string }) {
        return 'user' + '/' + userId
    },
    doc({ userId, profileId }: { userId: string, profileId: string }) {
        return this.col() + '/' + profileId // doesnt error eventhough some member is missing in this.col argument
    },
})

profile.col() // error shown correctly

consider this piece of code

there is no error even though in the tooltip it clearly needs an argument

however, the error is shown correctly if we try to access col via profile

playground

questions:

1. why is this happening?
2. how to solve this?

Answer 1

Most of the time I see the error that you posted, but if I hover just right I see the generic definition with (...args: any[]) .

Both col and doc are functions which return a string . If I use the generic to designate the args rather than the whole function, everything works as expected and I get an error. Does that work for you?

export const creator =  <
    C extends {},
    D extends {}
>(pathGenerator: {
    col: (props: C) => string,
    doc: (props: D) => string
}) => pathGenerator

export const profile = creator({
    col({ userId }:{ userId: string }) {
        return 'user' + '/' + userId
    },
    doc({ userId, profileId }: { userId: string, profileId: string }) {
        return this.col() + '/' + profileId // shows error!
    },
})

Playground Link