FOR LOOPS test

JavaScript performance comparison

Revision 5 of this test case created by getsetbro

Info

Difference between for/in, classical for loop and classical loop with caching.

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js">
</script>
<script>
Benchmark.prototype.setup = function() {
    var myArray = [];
    for (var i = 0; i < 1024; i++) {
      myArray.push(i);
    }
};
</script>

Test runner

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

Java applet disabled.

Testing in unknown unknown
Test Ops/sec
jQuery each 1
jQuery.each(myArray, function(elem, i) {
  myArray[i] = myArray[i]++;
});
pending…
for loop (no caching)
for (var i = 0; i < myArray.length; i++) {
  myArray[i] = myArray[i]++;
}
pending…
for loop (with caching)
for (var i = 0, l = myArray.length; i < l; i++) {
  myArray[i] = myArray[i]++;
}
pending…
jQuery.each (for comparison)
jQuery.map(myArray, function(elem, i) {
  return elem++;
});
pending…
for loop (no caching) - caching length
var length = myArray.length;
for (var i = 0; i < length; i++) {
  myArray[i] = myArray[i]++;
}
pending…
for loop (with caching) - caching length
var length = myArray.length;
for (var i = 0, l = length; i < l; i++) {
  myArray[i] = myArray[i]++;
}
pending…
for loop (with caching) - caching length, caching i
var len = myArray.length,
    i;
for (i = 0, l = len; i < l; i++) {
  myArray[i] = myArray[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