Fast Array Loops

JavaScript performance comparison

Revision 202 of this test case created by Chris Barr

Preparation code

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
      
<script>
Benchmark.prototype.setup = function() {
    // Populate the base array
    var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

};
</script>

Preparation code output

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
UnderscoreJS
_.each(arr, someFn);
pending…
jQuery
$.each(arr, someFn);
pending…
Array.ForEach
arr.forEach(someFn);
pending…
Standard JS Loop
for (var i = 0; i < arr.length; i++) {
  someFn(arr[i]);
}
pending…
Reversed Loop
for (var i = arr.length - 1; i >= 0; i--) {
  someFn(arr[i]);
}
pending…
Loop with length defined once
for (var i = 0, len = arr.length; i < len; i++) {
  someFn(arr[i]);
}
pending…

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Revisions

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