for vs forEach

JavaScript performance comparison

Revision 27 of this test case created by cfddream

Info

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

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
 
<script>
  Benchmark.prototype.setup = function() {
       var i, values = [],
          sum = 0;
      for (i = 0; i < 10000; i++) {
       values[i] = i;
      }
      
      function add(val) {
       sum += val;
      }
  };

  Benchmark.prototype.teardown = function() {
     var i=0, values = [],
          sum = 0;
  };
</script>

Preparation code output

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in unknown unknown
Test Ops/sec
forEach
 
values.forEach(add);
 pending…
for loop, simple
 
for (i = 0; i < values.length; i++) {
 add(values[i]);
}
 pending…
for loop, cached length
 
var len = values.length;
for (i = 0; i < len; i++) {
 add(values[i]);
}
 pending…
for loop, reverse
 
for (i = values.length - 1; i >= 0; i--) {
 add(values[i]);
}
 pending…
for loop, cached length, no callback
 
var len = values.length;
for (i = 0; i < len; i++) {
 sum += values[i];
}
 pending…
for loop, cached length, using function.call and supplying index and original array
 
var len = values.length;
for (i = 0; i < len; i++) {
 add.call(values, values[i], i, values);
}
 pending…
$.each
 
$.each(values, function(key, value) {
  add(value);
});
 pending…
for ... in
 
for (var v in values) {
 sum += v;
}
 pending…
for loop, reverse2
 
for (i = values.length; i--;) {
 add(values[i]);
}
 pending…

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

0 comments

Add a comment