Iterators are slover

iterator-vs-array.js

function time(f) {
  var start = Date.now()
  f()
  return Date.now() - start
}

var array = new function() {
  var value = [], i = 0
  while (i < 100000) value.push(i++)
  return value
}

var iterator = function() {
  var i = 0
  while (i < 100000) yield i++
}

function increment(x) { return x + 1 }
function isOdd(n) { return n % 2 }

var iteratorTime = time(function() {
  for each (let x in iterator()) {
    if (isOdd(x)) increment(x)
  }
})

var arrayTime = time(function() {
  array.filter(isOdd).forEach(increment)
})

iteratorTime - arrayTime 
/*
32
*/

Unfortunately this does not works http://jsperf.com/moz-iterators