Fastest array loops in Javascript

JavaScript performance comparison

Revision 395 of this test case created by Patrick Denny

Preparation code

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

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

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
For loop, basic
for (var i = 0; i < arr.length; i++) {
  someFn(i);
}
pending…
While loop, basic
var i = 0;
while (i < arr.length) {
  someFn(i);
  i++;
}
pending…
For loop, ++i < len
for (var i = 0, len = arr.length; ++i < len;) {
  someFn(i);
}
pending…
For loop, i--
for (var i = arr.length; i--; ) {
  someFn(i);
}
pending…
while loop, i--
var i = arr.length;
while (i--) {
  someFn(i);
}
pending…
while loop, ++i < len
var i = -1,
  len = arr.length;
while (++i < len) {
  someFn(i);
}
pending…

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Revisions

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