caching length

JavaScript performance comparison

Revision 22 of this test case created by rustinlee

Preparation code

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.7.0/lodash.min.js"></script>
      
<script>
Benchmark.prototype.setup = function() {
  var arr = [];
  for (var i = 0; i < 5000; i++) {
    arr[i] = Math.random();
  }

};
</script>

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
while loop
var len = arr.length;
while (len--) {
  arr[len] *= 2;
}
pending…
do-while loop
var len = arr.length;
do {
  arr[len] *= 2;
} while (len--);
pending…
Prefix Increment
for (var i = 0; i < arr.length; ++i) {
  arr[i] *= 2;
}
pending…
Prefix + Cached
for (var i = 0, len = arr.length; i < len; ++i) {
  arr[i] *= 2;
}
pending…
Array map
arr.map(function(el) {
  return el * 2;
});
pending…
Reverse cached
for (var i = arr.length - 1; i >= 0; i--) {
  arr[i] *= 2;
}
pending…
lodash 3.7.0 each
_.each(arr, function (n, i) {
  arr[i] = n * 2;
});
pending…
lodash 3.7.0 each 2
_.each(arr, function (n, i) {
  arr[i] *= 2;
});
pending…

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Revisions

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