Fastest array loops in Javascript (v135)

Revision 135 of this benchmark created on

Preparation HTML

<script>
  // Populate the base array
  var arr = [.0,.1,.2,.3,.4,.5,.6,.7,.8,.9,.0,.1,.2,.3,.4,.5,.6,.7,.8,.9,.0,.1,.2,.3,.4,.5,.6,.7,.8,.9,.0,.1,.2,.3,.4,.5,.6,.7,.8,.9,.0,.1,.2,.3,.4,.5,.6,.7,.8,.9];

  function someFn(ix) {
    return ix * 5 + 1 / 3 * 8;
  }
</script>

Test runner

Ready to run.

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

Revisions

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