for vs forEach

JavaScript performance comparison

Revision 136 of this test case created by Sander Elias

Preparation code

<script>
  var i, values = [],
      sum = 0;
  for (i = 0; i < 10000; i++) {
   values[i] = i;
  }
  
  function add(val) {
   sum += val;
  }
Array.prototype.seForEach = function(callback) {
  var a=this,l = a.length, x=0;
  while (x<l) {
     callback(a[x], x, a);
     x += 1
  }
  console.log(x) //do something with X!
};
</script>
    

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
forEach
values.forEach(add);
pending…
for loop, simple, cached length
var x = 0,
  l = values.length;
for (x = 0; x < l; x += 1) {
  add(values[x]);
}
console.log(x)
pending…
While loop, same as prototype
var l = values.length,
  x = 0,
  callback = add;
while (x < l) {
  callback(values[x], x, values);
  x += 1
}
console.log(x)
pending…
While loop, same as prototype but without callback!
var l = values.length,
  x = 0;
while (x < l) {
  add(values[x]);
  x += 1
}
console.log(x)
pending…
own iterpertation of forEach
values.seForEach(add);
pending…

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Revisions

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