Haskell-esque `zip` and `zipWith`, ported to node.js / CoffeeScript

zip.coffee

zip = (arr1, arr2) ->
  basic_zip = (el1, el2) -> [el1, el2]
  zip_with basic_zip, arr1, arr2

# I wrote two implementations of `zipWith`: one is iterative, and one is recursive. Feel free to do some benchmarks if you feel like it :)

# zip_with, iterative style
zip_with = (func, arr1, arr2) ->
  min = Math.min arr1.length, arr2.length
  ret = []
  
  for i in [0...min]
    ret.push func(arr1[i], arr2[i])
  
  ret

# zip_with, recursive style
zip_with_recursive = (func, arr1, arr2) ->
  return [] if arr1.length is 0 or arr2.length is 0
  
  el1 = arr1.shift()
  el2 = arr2.shift()
  
  ret_arr = zipWith func, arr1, arr2
  ret_arr.unshift func(el1, el2)
  
  ret_arr

# very short (too short) test
assert = require 'assert'
test_zip = ->
  assert.equal zip([1, 2, 3], [4, 5, 6]), [[1, 4], [2, 5], [3, 6]]
  
  add = (el1, el2) -> el1 + el2
  assert.equal zip_with(add, [1, 2, 3], [4, 5, 6]), [5, 7, 9]