'for' vs 'for in' loop speed (v3)

Revision 3 of this benchmark created on

Preparation HTML

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js">
</script>
<script>
  var arr = [];
  for (var i = 0; i < 100000; i++) {
    arr.push(i);
  }
  
  var obj = {};
  for (var i = 0; i < 100000; i++) {
    obj[i] = i;
  }
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
for loop
var sum = 0;
for (var i = 0; i < arr.length; i++) {
  sum += arr[i];
}
window.sum = sum;
ready
for in loop
var i, sum = 0;
for (i in arr) {
  sum += arr[i];
}
window.sum = sum;
ready
for loop 2
var sum = 0;
for (var i = 0, len = arr.length; i < len; i++) {
  sum += arr[i];
}
window.sum = sum;
ready

Revisions

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