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

delete vs undefined vs null (v22)

Revision 22 of this benchmark created by Thorsten Lorenz on October 18, 2013

Description

The delete operator removes a property entirely. Setting a property to undefined removes the value. Setting a property to null changes the value to the null value.

Technically they are not equivalent, but in practice they are often used to mean the same thing: that a property is unset.

Setup

var o = {
    };

Test runner

Ready to run.

Testing in
Test		Ops/sec
Delete	`delete o.p;`	ready
Set to False	`o.p = false;`	ready
Set to Zero	`o.p = 0;`	ready
Set to Null	`o.p = null;`	ready
Set to Undefined	`o.p = undefined;`	ready
Set to void 0	`o.p = void 0;`	ready

Revisions

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

Revision 1: published on September 23, 2010
Revision 2: published on October 13, 2010
Revision 3: published on October 28, 2010
Revision 4: published on October 24, 2011
Revision 6: published on April 28, 2012
Revision 7: published by BinaryKitten on November 6, 2012
Revision 8: published on December 3, 2012
Revision 9: published on December 3, 2012
Revision 10: published on December 7, 2012
Revision 11: published on January 12, 2013
Revision 12: published on February 25, 2013
Revision 13: published by Ian Nartowicz on March 18, 2013
Revision 14: published on March 31, 2013
Revision 15: published on April 29, 2013
Revision 16: published on June 1, 2013
Revision 17: published on July 11, 2013
Revision 18: published by narushevich on August 21, 2013
Revision 19: published by Dan on August 28, 2013
Revision 20: published on September 5, 2013
Revision 21: published on September 20, 2013
Revision 22: published by Thorsten Lorenz on October 18, 2013
Revision 23: published by Dan on November 15, 2013
Revision 24: published on December 5, 2013
Revision 26: published by S on May 23, 2014
Revision 27: published by Gary on May 26, 2014
Revision 28: published on July 12, 2014
Revision 29: published on September 5, 2014
Revision 30: published on September 28, 2014
Revision 31: published on December 1, 2014
Revision 32: published by Arjun on December 18, 2014
Revision 33: published by Mike McKenzie on December 18, 2014
Revision 34: published by Midel on January 25, 2015
Revision 35: published by Check if defined before delete on January 27, 2015
Revision 37: published on March 4, 2015
Revision 38: published by Paul on March 15, 2015
Revision 39: published by LJ_1102 on March 28, 2015
Revision 40: published on March 30, 2015
Revision 41: published on March 30, 2015
Revision 42: published on April 1, 2015
Revision 44: published on April 6, 2015
Revision 45: published on May 5, 2015
Revision 46: published on May 6, 2015
Revision 47: published on May 11, 2015
Revision 48: published by liene on May 22, 2015
Revision 49: published on June 2, 2015
Revision 50: published on June 8, 2015
Revision 51: published by Alex on June 16, 2015
Revision 93: published by Nikolay Emrikh on April 26, 2019
Revision 102: published by Th0rN13 on September 25, 2019
Revision 103: published by Th0rN13 on September 25, 2019
Revision 105: published by Rick Zhou on October 17, 2019
Revision 107: published by Marcell Toth on October 20, 2019
Revision 108: published by Marcell Toth on October 20, 2019
Revision 110: published by Thom Morais on October 24, 2019
Revision 111: published on January 13, 2020
Revision 123: published by Mike Lysikov on June 29, 2020
Revision 124: published by Mike Lysikov on June 29, 2020