Comparison of comparisons

JavaScript performance comparison

Test case created by minitech on 23rd June 2012

Info

Compares the performance of == and ===.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var a = 'hello';
    var b = 'world';
    var c = 'hello';
  };
</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
Identity	`a === b; a === c;`	pending…
Equality	`a == b; a == c;`	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:

Revision 1: published by minitech on 23rd June 2012
Revision 4: published on 1st November 2012
Revision 7: published on 16th January 2013
Revision 8: published on 21st March 2013
Revision 9: published on 13th May 2013

4 comments

Ben commented on 2nd October 2012: ∞

Identity is infinitely faster than equality. Checkout my results for proof.

http://screencast.com/t/II6KUTyqr

billy commented on 6th December 2012: ∞

Agreed with Ben, chrome will optimize this.

Lonesome Walker commented on 8th January 2013: ∞

fyi in ie9:

Identity a === b; a === c; 20,206,844 ±0.23%25% slower

Equality a == b; a == c; 27,134,240 ±0.68%fastest

Well, my firefox says: Identity a === b; a === c; 819,540,161 ±0.26%fastest

Equality a == b; a == c; 38,048,899 ±0.50%95% slower

So, it depends ;)

Tim Down commented on 28th February 2013: ∞

Clearly it varies with browser. Since these particular comparisons are defined by the ECMAScript spec to run precisely the same steps, this is an unsurprising result: it's bound to be engine-dependent.