for loop research

JavaScript performance comparison

Test case created by

Preparation code


      
      <script>
Benchmark.prototype.setup = function() {
  var arr = [];
  
  for (var i=0; i<1000; i++) {
    arr.push('arr-value-' + i);
  }
  
  function worker() {
    return(1+1);
  }

};
</script>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
classic for-loop
for (var i=0; i < arr.length; i++) {
  worker();
}
pending…
++i
for (var i=0; i < arr.length; ++i) {
  worker();
}
pending…
caching length in loop
for (var i=0, len=arr.length; i<len; i++) {
  worker();
}
pending…
caching length outside loop
var len=arr.length;

for (var i=0; i<len; i++) {
  worker();
}
pending…
double caching length
var len=arr.length;

for (var i=0, ilen=len; i<ilen; i++) {
  worker();
}
pending…
while alternative i--
var i = arr.length;
while (i--) {
  worker();
};
pending…
while alternative --i
var i = arr.length;
while (--i) {
  worker();
};
pending…

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Revisions

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