# Uses a binary search algorithm to locate a value in the specified array. binary_search = (items, value) -> start = 0 stop = items.length - 1 pivot = Math.floor (start + stop) / 2 while items[pivot] isnt value and start < stop # Adjust the search area. stop = pivot - 1 if value < items[pivot] start = pivot + 1 if value > items[pivot] # Recalculate the pivot. pivot = Math.floor (stop + start) / 2 # Make sure we've found the correct value. if items[pivot] is value then pivot else -1 # Test the function. console.log 2 is binary_search [10, 20, 30, 40, 50], 30 console.log 4 is binary_search [-97, 35, 67, 88, 1200], 1200 console.log 0 is binary_search [0, 45, 70], 0 console.log(-1 is binary_search [0, 45, 70], 10)