Create type which requires only the specified fields-CodePudding

Assume I have a type

type A = {
  a: string
  b?: number
  c: boolean
  d?: string
}

How could I derive a type from it where I only require a and b and leave everything else optional

type A2 = {
  a: string
  b: number
  c?: boolean
  d?: string
}

My approach was:

export type WithRequiredOnly<T, K extends keyof T> = T & { [P in K]-?: T[P] } & { [P in Exclude<keyof T, K>] ?: T[P] }

A2 = WithRequiredOnly<A, 'a'|'b'>

But this seems to still require the other fields...

CodePudding user response：

type WithRequiredOnly<T, K extends keyof T> = Required<Pick<T, K>> & Partial<Omit<T, K>>