/examples/beautiful_code/binary_search.coffee

 1# Beautiful Code, Chapter 6.
 2# The implementation of binary search that is tested.
 3
 4# Return the index of an element in a sorted list. (or -1, if not present)
 5index = (list, target) ->
 6  [low, high] = [0, list.length]
 7  while low < high
 8    mid = (low + high) >> 1
 9    val = list[mid]
10    return mid if val is target
11    if val < target then low = mid + 1 else high = mid
12  return -1
13
14console.log 2 is index [10, 20, 30, 40, 50], 30
15console.log 4 is index [-97, 35, 67, 88, 1200], 1200
16console.log 0 is index [0, 45, 70], 0