Browser Diet - Cache Array Length

JavaScript performance comparison

Revision 10 of this test case created by Zeno Rocha

Preparation code

<script>
  var arr = new Array(1000),
      len, i;
</script>

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Testing in unknown unknown
Test Ops/sec
Without cache
for (i = 0; i < arr.length; i++) {
  // do something
}
pending…
With cache
for (i = 0, len = arr.length; i < len; i++) {
  // do something
}
pending…

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Revisions

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2 comments

k.zarvansky commented :

or use simply for (i = arr.length; i >= 0; i--) { // do something }

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