[Typescript] getProp<T, P extends PathKeys<T>>(obj: T, path: P): PropType<T, P>

const obj = {
  name: "John",
  age: 33,
  cars: [
    { make: "Ford", age: 10 },
    { make: "Tesla", age: 2 },
  ],
} as const;

export type PathKeys<T> = T extends object ? string: T extends readonly any[]
  ? Extract<keyof T, `${number}`> | SubKeys<T, Extract<keyof T, `${number}`>>
  : T extends object
  ? Extract<keyof T, string> | SubKeys<T, Extract<keyof T, string>>
  : never;

export type SubKeys<T, K extends string> = K extends keyof T ? `${K}.${PathKeys<T[K]>}` : never;

export type PropType<T, Path extends string> = Path extends keyof T
  ? T[Path]
  : Path extends `${infer K}.${infer RT}`
  ? K extends keyof T
    ? PropType<T[K], RT>
    : unknown
  : unknown;

declare function getProp<T, P extends PathKeys<T>>(
  obj: T,
  path: P
): PropType<T, P>;

const make = getProp(obj, 'cars.0.make') // const make: "Ford"