javascript function memoization benchmark

fibonacci_benchmark.coffee

fib1 = (index) ->
  if index < 2
    1
  else
    fib1(index - 1) + fib1(index - 2)

fib2 = (index) ->
  hash = {}
  fib2 = (index) ->
    hash[index] or= if index < 2
      1
    else
      fib2(index - 1) + fib2(index - 2)
  fib2(index)

runtime = (start, end) ->
  (end.getTime() - start.getTime()) / 1000

benchmark = (max) ->

  start1 = new Date
  fib1(i) for i in [0..max]
  end1 = new Date

  start2 = new Date
  fib2(i) for i in [0..max]
  end2 = new Date

  run1 = runtime(start1, end1)
  run2 = runtime(start2, end2)
  
  console.log "Recursion: #{run1}s"
  console.log "Memoized Recursion: #{run2}s"

benchmark 40