Fastest array loops in Javascript (v352)

Revision 352 of this benchmark created on

Preparation HTML

<script>
  // Populate the base array
  var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }

  var dest;

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

Test runner

Ready to run.

Testing in
TestOps/sec
While length--
var l = arr.length;
while (l--) {
  someFn(arr[l]);
}
ready
While length--
var l = arr.length;
while (l--) {
  someFn(arr[l]);
}
ready
For loop, cached
for (var i = 0, len = arr.length; i < len; i++) {
  someFn(arr[i]);
}
ready
For loop, cached out of scope
len = arr.length;
for (var i = 0; i < len; i++) {
  someFn(arr[i]);
}
ready
Do-while loop, --i
var i = arr.length;
if (i > 0) {
  do {
    someFn(arr[i]);
  }
  while (--i);
}
ready
For..in loop
for (var i in arr) {
  someFn(arr[i]);
}
ready
Order
while (i = arr.shift()) {
  someFn(i);
}
ready
forEach
arr.forEach(function(v) {
  someFn(v)
})
ready
order validation
while ((i = arr.shift()) !== undefined) {
  someFn(i);
}
ready
While ! Undefined
var a;
while ((a = arr[i++]) !== undefined) {
  someFn(a);
}
ready
Pop
while (i = arr.pop()) {
  someFn(i);
}
ready
Order w/ array copy
var copy = arr.slice(0);
while (i = copy.shift()) {
  someFn(i);
}
ready
While length--
var l = arr.length;
while (l--) {
  someFn(arr[l]);
}
ready
.Net Style For Loops
for (var i = 0, x; x = arr[i]; ++i) {
  someFn(x);
}
ready

Revisions

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