caching length

JavaScript performance comparison

Revision 43 of this test case created by Jonathan Rowny

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 CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
MR
for (var i = 0, len = arr.length; i < len; i++) {
  arr[i] *= 2;
}
pending…
not cached
for (var i = 0; i < arr.length; i++) {
  arr[i] *= 2;
}
pending…
u wot m8
var len = 2;
len *= arr.length;
len -= len / 2;
for (var i = 0; i < len; i++) {
  arr[i] *= 2;
}
pending…
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
arr.map(function(el) {
  return arr.length;
});
pending…
Array map
var len = arr.length;
arr.map(function(el) {
  return len;
});
pending…

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Revisions

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