pipe.ts

const pipe = <T, K>(
  iterable: IterableIterator<T>,
  seed: K,
  fn: (a: T) => K
): T => {
  const iterator = iterable[Symbol.iterator]()
  if (iterable instanceof GeneratorFunction) {
    iterator.next()
  }
  let result = iterator.next(seed)
  while (!result.done) {
    result = iterator.next(fn(result.value))
  }
  return result.value
}