export type Paths<T, D extends number = 2> = [D] extends [never]
  ? never
  : T extends { [key: string]: unknown }
  ? {
      [K in keyof T]-?: K extends string | number
        ? `${K}` | Join<K, Paths<T[K], Prev[D]>>
        : never
    }[keyof T]
  : ''
export type Join<K, P> = K extends string | number
  ? P extends string
    ? `${K}${'' extends P ? '' : '.'}${P}`
    : never
  : never

export type Prev = [never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...Array<0>]

export type Leaves<T, D extends number = 1> = [D] extends [never]
  ? never
  : T extends { [key: string]: unknown }
  ? { [K in keyof T]-?: Join<K, Leaves<T[K], Prev[D]>> }[keyof T]
  : ''