Simple perf test of loops

test.coffee

measure = (t, f) ->
  s = new Date()
  s = s.getTime()
  ret = f()
  e = new Date()
  console.log t, e.getTime() - s, ret

test1 = ->
  r = 0
  for x in a
    r += x
  return r

test2 = ->
  r = 0
  l = a.length
  while l
    r += a[--l]
  return r

console.log "data creation"
a = (Math.round((Math.random() - 0.5) * 100) for i in [1..1000000])

console.log "test start"

measure "for(;;)", test1
measure "while()", test2

test1-mod.js

// Generated by CoffeeScript 1.9.3
var a, i, measure, test1, test2;

measure = function(t, f) {
  var e, ret, s;
  s = new Date();
  s = s.getTime();
  ret = f();
  e = new Date();
  return console.log(t, e.getTime() - s, ret);
};

test1 = function() {
  var j, len, r, x;
  r = 0;
  for (j = 0, len = a.length; j < len; j++) {
    x = a[j];
    r += x;
  }
  return r;
};

test2 = function() {
  var l, r;
  r = 0;
  l = a.length;
  while (l) {
    r += a[--l];
  }
  return r;
};

console.log("data creation");

a = (function() {
  var j, results;
  results = [];
  for (i = j = 1; j <= 1000000; i = ++j) {
    results.push(Math.round((Math.random() - 0.5) * 100));
  }
  return results;
})();

console.log("test start");

measure("for(;;)", test1);

measure("while()", test2);


// // // // // // // // // // // // // // // // // // // // // // // // 
// Manually added

test3 = function() {
  var r, x;
  r = 0;
  for(x of a) {
    r += x;
  }
  return r;
}

test4 = function() {
  var r, iterator;
  r = 0;
  iterator = a[Symbol.iterator]()
  while(!(it = iterator.next()).done) {
    r += it.value;
  }
  return r;
}

test4 = function() {
  var r, iterator;
  r = 0;
  iterator = a[Symbol.iterator]()
  while(!(it = iterator.next()).done) {
    r += it.value;
  }
  return r;
}

measure("for of  ", test3);
measure("iterator", test4);