sensible comparison function for js

cmp.coffee

# comparison function, checking also the contents of elements if we are comparing 2 arrays.
# very useful for sorting.

cmp = (a,b) ->
  typemap =
    'null': 0
    'undefined': 0
    'number': 1
    'string': 1
    'object': 2
  if typemap[typeof a] > typemap[typeof b]
    return 1
  else if typemap[typeof a] < typemap[typeof b] 
    return -1
  if (typeof a) == 'object' and Array.isArray a
    elemCmp = 0
    [0...Math.min(a.length,b.length)].some (i) ->
      elemCmp = cmp a[i], b[i]
      elemCmp != 0
    return elemCmp or cmp a.length, b.length
  if a > b
    return 1
  else if a < b
    return -1
  return 0


one = [2, 10]
two = [2, 5, 10]
three = [2, 5, 5]
four = [2, 10, -1]

l_unsorted = [one, two, three, four]
l_sorted = l_unsorted[..]
l_sorted.sort cmp

console.info l_unsorted, '-->', l_sorted

assert = require 'assert'
assert.deepEqual l_sorted, [three, two, one, four]