Unionize Deep

unionizeDeep.ts

type MarkUndefinable<A, B> = {
  [K in keyof A]: A[K] extends O.Object
  ? MarkUndefinable<A[K], A.At<B, K>>
  : K extends keyof B ? A[K] | undefined : A[K]
}

type UnionizeDeep<A extends object, B extends object> =
  O.Merge<MarkUndefinable<A, B>, B, 'deep', M.BuiltIn, undefined>

type test = A.Compute<UnionizeDeep<{
  name?: string,
  age?: string,
  details: {
    ccn: string,
    address: {
      no: string
      name: string
    }
  }
}, {
  name: {
    first: string
    last: string
  },
  age?: number,
  details: {
    ccv: string
    address: {
      no: number
      name: string
    }
  }
}>>