Fastest array loops in Javascript (v31)

Revision 31 of this benchmark created on

Preparation HTML

<script>
  // Populate the base array
  var arr = [],
      ret;
  for (var i = 1; i <= 50; i++) {
    arr[i] = i;
  }

  function someFn(x) {
    return x + x;
  }
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
For loop, basic
for (var i = 0; i < arr.length; i++) {
  ret = someFn(i);
}
ready
While loop, basic
var i = 0;
while (i < arr.length) {
  ret = someFn(i);
  i++;
}
ready
For loop, cached
for (var i = 0, len = arr.length; i < len; i++) {
  ret = someFn(i);
}
ready
For loop, i--
for (var i = arr.length - 1; i >= 0; i--) {
  ret = someFn(i);
}
ready
Do-while loop, i--
var i = arr.length - 1;
do {
  ret = someFn(i);
}
while (i--);
ready
Do-while loop, --i
var i = arr.length;
if (i > 0) {
  do {
    ret = someFn(i);
  }
  while (--i);
}
ready

Revisions

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