moar tipezzzz

pipe.ts

const pipe = <T, K>(
  iterable: IterableIterator<T>,
  seed: K,
  fn: (a: T) => K
): T => {
  const iterator: IterableIterator<T> = iterable[Symbol.iterator]()
  
  if (iterable instanceof GeneratorFunction) {
    iterator.next()
  }

  let result: IteratorResult<T> = iterator.next(seed)

  while (result.done === false) {
    result = iterator.next(fn(result.value))
  }

  return result.value
}