Object keys iteration

JavaScript performance comparison

Revision 30 of this test case created by Pencroff

Info

Testing Object.keys vs for-in. I've added jQuery's .each() for my own testing.

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
 
<script>
Benchmark.prototype.setup = function() {
    var data = {};
    var data_copy = {};
     
      for (var k = 0; k < 750; k+=1) {
      if (k<500) {
       data[k] =  'user ' + k;
     } else {
       data[k] = undefined;
     }
     
      }
   
    var keys = Object.keys(data);
    var len = keys.length;
    var i = 0;
    var prop;
   
};
</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
for-in
for (var key in data) {
  data_copy[key] = data[key];
}
pending…
object-keys
Object.keys(data).forEach(function(element, index, array) {
  data_copy[element] = data[element];
});
pending…
object-keys 2
while (i < len) {
  prop = keys[i];
  data_copy[prop] = data[prop];
  i+=1;
}
pending…
object-keys 3
for (i = 0; i < len; i+=1) {
  prop = keys[i];
  data_copy[prop] = data[prop];
}
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