Suggestion: AddPropRecursively (or as you like)

[ftzi]

Hey! I searched a lot but couldn't find this type to use in my project, so I spent some hours learning more advanced typescript and came with this: (Maybe there is a type in this lib that does exactly this, but I really couldn't find / understand the Readme enough)

type AddPropDistributive<Obj extends {}, Prop> =
  { [K in keyof Obj]: (Obj[K] extends {} ? AddPropRecursively<Obj, Prop> : Obj[K]) };
type AddPropRecursively<Obj extends {}, Prop> =
  Obj & Prop & AddPropDistributive<Obj, Prop>;

Usage:

You have any type object, let's say

type A = {
  B: number,
  C: {
    D: string
  },
  E: {
    F: {
      G: boolean
   }
}

type X = AddPropRecursively<A, {_new: number}>

X is = {
  _new: number,
  B: number,
  C: {
    _new: number,
    D: string
  },
  E: {
    _new: number,
    F: {
      _new: number,
      G: boolean
   }
}