pickProps.ts

type StrLen<T extends string, R extends Array<string> = []> = T extends `${infer C}${infer P}`
  ? StrLen<P, [...R, C]>
  : R['length']

type StrSplit<T extends string, S extends string, R extends Array<string> = []> = T extends `${infer X}${S}${infer Y}`
  ? StrSplit<Y, S, StrLen<X> extends 0 ? R : [...R, X]>
  : StrLen<T> extends 0
  ? R
  : [...R, T]

type TailProp<T extends string> = T extends `${string}.${infer U}` ? TailProp<U> : T

type PickSource<T extends Array<string>, S extends Record<string, any> = {}> = {
  [K in T[number] as TailProp<K>]: PickSourceDeep<K, S>
}

type ParseInt<T> = T extends `${infer N extends number}` ? N : never

type PickSourceDeep<
  T extends string,
  S extends Record<string, any> | Array<unknown> = {},
  __Sp extends Array<string> = StrSplit<T, '.'>,
  __R = never,
> = __Sp extends [infer C, ...infer R]
  ? S extends Array<unknown>
    ? PickSourceDeep<
        never,
        NonNullable<Extract<S[ParseInt<C>], Array<unknown> | Record<string, any>>>,
        R extends Array<string> ? R : [],
        S[ParseInt<C>]
      >
    : C extends keyof S
    ? PickSourceDeep<
        never,
        NonNullable<S[C]> extends Record<string, any> ? NonNullable<S[C]> : never,
        R extends Array<string> ? R : [],
        S[C]
      >
    : unknown
  : __R

function pickProps<T extends Record<string, any>, K extends Array<Extract<keyof T, string>> | Array<string>>(
  source: T,
  keys: K,
): Partial<PickSource<K, Required<T>>> {
  const result: Partial<PickSource<K, Required<T>>> = Object.create(null)

  keys.forEach((key) => {
    if (typeof key === 'string') {
      let keyPath = key.split('.')

      Reflect.set(
        result,
        keyPath[keyPath.length - 1],
        keyPath.reduce<unknown>((s, k) => (typeof s === 'undefined' ? s : Reflect.get(s!, k)), source),
      )
    } else {
      Reflect.set(result, key, Reflect.get(source, key))
    }
  })

  return result
}

Usage:

interface UU {
  name: string
  age: number
  data: Array<{ oo: string; ko: boolean }>
  addr: {
    pa: boolean
    pp: {
      kk: string
      ee: {
        oi: number
      }
    }
  }
}

const ddd: Partial<UU> = {
  name: 'zrian',
  age: 19,
  data: [
    { oo: 'asd', ko: true },
    { oo: 'asdas', ko: false },
  ],
  addr: {
    pa: true,
    pp: {
      kk: 'asdasda',
      ee: {
        oi: 1000,
      },
    },
  },
}

let d = pickProps(ddd, ['name', 'addr.pp', 'addr.pp.ee'])