Fastest array loops in Javascript

JavaScript performance comparison

Revision 343 of this test case created by Rulin

Preparation code

<script>
    // Populate the base array
    var arr = [];
    for (var i = 0; i < 1000; i++) {
        arr[i] = 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(arr[i]);
}
pending…
for loop - cache length in for loop
for (var i = 0, len = arr.length; i < len; i++) {
    someFn(arr[i]);
}
pending…
for loop - cache length outside
var len = arr.length;
for (var i = 0; i < len; i++) {
    someFn(arr[i]);
}
pending…
for loop - reverse - basic
for (var i = arr.length; i;) {
    i--;
    someFn(arr[i]);
}
pending…
for loop - reverse - cache length outside
var len = arr.length;
for (var i = len; i;) {
    i--;
    someFn(arr[i]);
}
pending…

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Revisions

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