path-value.type.ts

export type PathImpl<T, Key extends keyof T> = Key extends string
  ? T[Key] extends Record<string, any>
    ?
        | `${Key}.${PathImpl<T[Key], Exclude<keyof T[Key], keyof any[]>> &
            string}`
        | `${Key}.${Exclude<keyof T[Key], keyof any[]> & string}`
    : never
  : never;

export type PathImpl2<T> = PathImpl<T, keyof T> | keyof T;

export type Path<T> = keyof T extends string
  ? PathImpl2<T> extends string | keyof T
    ? PathImpl2<T>
    : keyof T
  : never;

export type PathValue<
  T,
  P extends Path<T>,
> = P extends `${infer Key}.${infer Rest}`
  ? Key extends keyof T
    ? Rest extends Path<T[Key]>
      ? PathValue<T[Key], Rest>
      : never
    : never
  : P extends keyof T
  ? T[P]
  : never;