for loop length caching

JavaScript performance comparison

Revision 4 of this test case created

Preparation code

<script>
  var arr = [],
      counter = 0;
 
  while (arr.length < 10000000) {
   arr[arr.length] = Math.floor(Math.random() * 16383);
  }
</script>

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Testing in unknown unknown
Test Ops/sec
No caching
for (var i = 0; i < arr.length; i++) {
 counter += arr[i];
}
pending…
Length property caching
for (var i = 0, length = arr.length; i < length; i++) {
 counter += arr[i];
}
pending…

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