Function.prototype.perf (just for concept)

performer.coffee

_ = require('underscore-contrib')


# ------------------------------------------ Helpers
middle = (x, y) -> (x + y) / 2
getter = _.curry2(_.flip(_.nth))

# ------------------------------------------ Perf definition
Function.prototype.perf = do ->
  logs = {}

  sFrom = getter(0)
  msFrom = getter(1)

  middleFromTime = (x, y) ->
    return [
      middle sFrom(x), sFrom(y)
      middle msFrom(x), msFrom(y)
    ]

  formatTime = (time) -> "#{sFrom(time)}s #{msFrom(time)/1000000}ms"

  id = 0
  return ->
    funcID = id++
    logs[funcID] = []

    orig = @
    return ->
      from = process.hrtime()
      results = orig.apply(@, arguments)
      endTime = process.hrtime(from)

      logsArray = logs[funcID]
      logsArray.push(endTime)

      middleTime = logsArray.reduce(middleFromTime, logsArray[0])

      console.log('Execution time:', formatTime(endTime), ' //', 'Middle time:', formatTime(middleTime))

      return results


# ------------------------------------------ Example
do ->
  start = 3000
  maxV = start + 1

  getRandom = (acc, max) ->
    while acc.indexOf(random) isnt -1
      random = Math.floor(Math.random() * max) + 1
    random

  randomize = ((acc, l, max) ->
    if l < 0 then acc else randomize(acc.concat([getRandom(acc, max)]), l - 1, max)
  )

  custom = (-> randomize([], start, maxV)).perf()

  custom()
  custom()
  custom()
  custom()
  
### response like:
Execution time: 0s 251.843461ms  // Middle time: 0s 251.843461ms
Execution time: 0s 341.344683ms  // Middle time: 0s 296.594072ms
Execution time: 0s 259.171552ms  // Middle time: 0s 277.882812ms
Execution time: 0s 275.119679ms  // Middle time: 0s 276.5012455ms
###

Function.prototype.perf === Function::perf