for vs forEach (v286)

Revision 286 of this benchmark created by Tomasz on

Description

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

Preparation HTML

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

  function iterate(values, callback, scope) {
    for(var i = 0, len = values.length; i < len; i++ ) {
      callback.call(scope, values[i], i);
    } 
  }

</script>

Test runner

Ready to run.

Testing in
TestOps/sec
forEach
values.forEach(add);
ready
for loop, simple
for (i = 0; i < values.length; i++) {
  add(values[i]);
}
ready
for loop, cached length
var len = values.length;
for (i = 0; i < len; i++) {
  add(values[i]);
}
ready
for loop, reverse
for (i = values.length - 1; i >= 0; i--) {
  add(values[i]);
}
ready
forEach more local
(function() {
  var sum = 0;
  values.forEach(function(val) {
    sum += val;
  });
})();
ready
forEach without closure
result.sum = 0;
values.forEach(function(val) {
  this.sum += val;
}, result);
 
ready
use custom iterate method
result.sum = 0;
iterate(values, function(val) {
  this.sum += val;
}, result);
 
ready

Revisions

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