for vs forEach

JavaScript performance comparison

Revision 123 of this test case created by Chen-Pang He

Info

Is it faster to use the native forEach or just loop with for?

Preparation code

<script>
  var i, values = [],
      sum = 0;
  for (i = 0; i < 10000; i++) {
   values[i] = i;
  }
 
  function add(val) {
   sum += val;
  }

Array.prototype.each = function (callback)
{
    for (var i = this.length - 1; i >= 0; i--)
        callback (this[i]);
}
</script>

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Testing in unknown unknown
Test Ops/sec
forEach
values.forEach(add);
pending…
Homemade each
values.each(add)
pending…
For loop, queue
var len = values.length;
var sum = 0;
for (i = 0; i < len; i++) {
  sum += values[i];
}
pending…
For loop, stack
var sum = 0;
for (var i = values.length - 1; i >= 0; i--) {
  sum += values[i];
}
pending…

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Revisions

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