Implement a generic RequiredByKeys<T, K> which takes two type argument T and K.
K specify the set of properties of T that should set to be required. When K is not provided, it should make all properties required just like the normal Required<T>.
For example
interface User {
name?: string
age?: number
address?: string
}
type UserRequiredName = RequiredByKeys<User, 'name'> // { name: string; age?: number; address?: string }
import type { Equal, Expect } from '@type-challenges/utils'
interface User {
name?: string
age?: number
address?: string
}
interface UserRequiredName {
name: string
age?: number
address?: string
}
interface UserRequiredNameAndAge {
name: string
age: number
address?: string
}
type cases = [
Expect<Equal<RequiredByKeys<User, 'name'>, UserRequiredName>>,
Expect<Equal<RequiredByKeys<User, 'name' | 'age'>, UserRequiredNameAndAge>>,
Expect<Equal<RequiredByKeys<User>, Required<User>>>,
// @ts-expect-error
Expect<Equal<RequiredByKeys<User, 'name' | 'unknown'>, UserRequiredName>>,
]