defi-mlb.html

---
layout: default
title: Défi de Matthias Le Brun
---
<section>
	<article>
    <div class="header">
			<h2>Défi de Matthias Le Brun</h2>
    </div>
		<p>Au tour de Matthias Le Brun de vous défier. En jeu, une place pour CaenJS à gagner pour le premier à avoir compléter le défi.</p>
		<p>Attention : Si vous jouez pour le fun, merci de ne pas publier la solution pour laisser à ceux qui jouent pour la place l'opportunité de gagner honnêtement ;).</p>
		<hr />
		<p>Pour commencer, ouvrez la console et suivez les instructions ;).</p>
		<hr />
		<p><a href="concours.html" title="Retour à la liste des défis">Retour</a></p>
	</article>
</section>
<script type="text/javascript">
;(function(){
  
  var tests = []
    , descriptions = []
    , attempts = []
    , mathRandom = Math.random
    , i = -1
    , done = false
    , log = function(){console.log.apply(console, arguments)}
    , warn = function(){console.warn.apply(console, arguments)}
    
  function pushAttempt(fn){
    attempts.push("test(" + fn.toString() + ")")
  }
 
  function test(any){
    var out
    if(done){
      log("You can tweet that :")
      log("@FranceJS I succeeded in the test : " + any)
      done = false
      return ":)"
    }
    if(any === "last"){
      log(descriptions[i])
      return
    }
    if(any === "start") {
      log(descriptions[++i])
      return
    }
    if(i == -1){
      log("Pass me 'start'")
      return 
    }
    if((out = tests[i](any)) === true) {
      log("Good!")
      log(descriptions[++i])
    } else if(out === false) {
      warn("Nope.")
    }
  }
  
  function complete(){
    log(attempts.join("\n\n\n\n"))
    log("Paste the previous output into a Gist and pass the link to the test function")
    done = true
  }
  
  function failed(){
    warn("Nope.")
  }
  
  function randomArray(min, l){
    var i = -1
      , l = arguments.length > 1 ? l >>> 0 : (min + ~~(mathRandom() * 6)) >>> 0
      , keys = Array(l)
    while(++i < l) keys[i] = ~~(mathRandom() * (1<<30))
    return keys
  }
  
  
  tests.push(propertiesTest)
  descriptions.push("Pass a function that returns all the owned property names of its first argument")
  function propertiesTest(fn){
    pushAttempt(fn)
    var keys = randomArray(5)
      , nonEnumerable = ~~(keys.length / 2)
      , i = -1, l = keys.length 
      , k, m
      , object = Object.create(null)
      , result
      , found
    while(++i < l) {
      if(nonEnumerable--){
        Object.defineProperty(object, keys[i], {value:mathRandom(), enumerable:false})
        continue
      }
      object[keys[i]] = mathRandom()
    }
    if(result = fn(object)) {
      if(result.length == l) {
        while(--l > -1) {
          k = -1, m = keys.length
          while(++k < m) {
            if(result[l] == keys[k]) {
              keys.splice(k, 1)
              break
            }
          }
        }
        return !keys.length
      }
    }
    return false
  }
  
  
  tests.push(iteratorTest)
  descriptions.push("Pass a function taking an array as first argument, which returns a function. \
The returned function should, at each call, return the next item in the array or null if there is no more\
If the array changes, it shouldn't impact the results of this function")
  function iteratorTest(fn){
    pushAttempt(fn)
    var l = 30 + ~~(mathRandom() * 30)
      , array = randomArray(l)
      , length = array.length
      , copy = array.concat()
      , i = -1
      , iterator = fn(array)
      , item
    while(item = iterator()) {
      if(copy[++i] !== item) {
        return false
      } 
      if(~~(mathRandom() * length) > .8 * length) {
        array.splice(i, 1)
      }
    }
    return item === null && ++i == length 
  }
  
  
  tests.push(UInt32test)
  descriptions.push("Pass a function that converts its first arguments into a UInt32")
  function UInt32test(fn){
    pushAttempt(fn)
    var array = randomArray(0, 32)
      , l = array.length
      , item
    while(--l) {
      if(fn(item = (array[l] << 4)) !== item >>> 0) return false
    }
    return true
  }
  
  
  tests.push(cookieTest)
  descriptions.push("Pass a function which returns the value of the cookie that has the name passed as first argument")
  function cookieTest(fn){
    pushAttempt(fn)
    var succeeded = false
      , cookieName = "cookie" + String(~~(mathRandom() * (1<<30)))
      , value = String(~~(mathRandom() * (1<<30)))
    document.cookie = cookieName + "=" + value
    if(fn(cookieName) === value) succeeded = true
    document.cookie = cookieName + "=; expires=" + new Date().toGMTString()
    return succeeded
  }  
  
  tests.push(propertyTest)
  descriptions.push("Pass a function that returns an object which has an enumerable, read-only 'foo' property equal to 'bar' but that doesn't own it")
  function propertyTest(fn){
    pushAttempt(fn)
    var object = fn()
      , proto = Object.getPrototypeOf(object)
      , propertyDescriptor = Object.getOwnPropertyDescriptor(proto, "foo")
    
    return typeof propertyDescriptor == "object" && propertyDescriptor.configurable == false && propertyDescriptor.enumerable == true && propertyDescriptor.value == "bar" && propertyDescriptor.writable == false
  }
  
  tests.push(asyncTest)
  descriptions.push("Pass a function that takes a first `fn` argument, calling it every 200ms for 3 times with its last output as first argument as soon as you got the first output")
  function asyncTest(fn){
    pushAttempt(fn)
    var i = 7, shift = 3
    function runner(output){
      return i = (output === void 0 ? i : output) << ++shift
    }
    fn(runner)
    setTimeout(function(){
      if(229376 === i) complete()
      else failed()
    }, 2000)
  }
  
  window.test = test
  log("Hey! Pass 'start' to the `test` function")
  log("All the anwsers should be passed to `test`")
  log("Pass `last` if you want the last question")
    
})()
</script>