jsPerf.app is an online JavaScript performance benchmark test runner & jsperf.com mirror. It is a complete rewrite in homage to the once excellent jsperf.com now with hopefully a more modern & maintainable codebase.

jsperf.com URLs are mirrored at the same path, e.g:

https://jsperf.com/negative-modulo/2

Can be accessed at:

https://jsperf.app/negative-modulo/2

undefined (v9)

Revision 9 of this benchmark created by Anders Ringqvist on September 22, 2011

Preparation HTML

<script>
  var x;
</script>

Test runner

Ready to run.

Testing in
Test		Ops/sec
x === undefined	`x === undefined`	ready
typeof x === 'undefined'	`typeof x === 'undefined'`	ready
x === void 0	`x === void 0`	ready
!x	`!x`	ready
null	`x == null`	ready
[][0]	`x === [][0]`	ready
{}.x	`x === {}.x`	ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.

Revision 1: published by Ron on August 3, 2010
Revision 2: published on August 4, 2010
Revision 8: published on April 26, 2011
Revision 9: published by Anders Ringqvist on September 22, 2011
Revision 10: published on September 24, 2011
Revision 11: published by Anders Ringqvist on October 30, 2011
Revision 12: published by Anders Ringqvist on October 30, 2011
Revision 13: published by Anders Ringqvist on October 30, 2011