caching length

JavaScript performance comparison

Revision 64 of this test case created

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = Math.random();
    }
};
</script>

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Testing in unknown unknown
Test Ops/sec
Cached Inside
for (var i = 0, len = arr.length; i < len; i++) {
  arr[i] *= 2;
}
pending…
Prefix Increment
for (var i = 0; i < arr.length; i++) {
  arr[i] *= 2;
}
pending…
Prefix + Cached Inside
for (var i = 0, len = arr.length; i < len; i++) {
  arr[i] *= 2;
}
pending…
Array.forEach
arr.forEach(function(element, i) {
  arr[i] = element * 2;
});
pending…
Cached Outside
var maxI = arr.length;
for(var i = 0; i < maxI; i++) {
  arr[i] *= 2;
}
pending…

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