Forward Loop Vs Bakward Loop (javascript) (v4)

Revision 4 of this benchmark created on

Description

Just if you want to test the popular claim that looping backward in an array is faster than looping forward. Added a reverse while loop test as well, Looping backward is faster than forward loop and while reverse is better than all of the above.

Preparation HTML

<script>
  var arr = ["a", "b", "c", "d"];
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
forward loop
for (var i = 0; i < arr.length; i++) {
 alert(arr[i]);
}
ready
backward loop
for (var i = arr.length - 1; i >= 0; i--) {
 alert(arr[i]);
}
ready
backward while loop
var i = arr.length;
while (--i >= 0) {
 alert(arr[i]);
}
ready
foreach loop
for (var i in arr) {
 alert(arr[i]);
}
ready
backward no test
for (var i = arr.length; i--; ) {
 alert(arr[i]);
}
ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.