Equality operators with the same types

JavaScript performance comparison

Revision 4 of this test case created by Kyle Simpson on 22nd February 2011

Info

Test for == and === with the same operand types.

Preparation code

<script>
  var foo = 12,
      bar = 12,
      baz = "12";
</script>

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Testing in unknown unknown
Test		Ops/sec
Non-strict equal	`foo == bar;`	pending…
Strict equal	`foo === bar;`	pending…
different types, coercion	`foo == baz;`	pending…
different types, no coercion	`foo === baz;`	pending…

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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 Dmitry A. Soshnikov on 3rd August 2010
Revision 4: published by Kyle Simpson on 22nd February 2011
Revision 6: published on 14th April 2011
Revision 9: published on 4th May 2011
Revision 10: published by Tobias Reiss on 11th January 2012
Revision 11: published by Matthew Robb on 14th March 2012
Revision 12: published on 27th December 2012
Revision 13: published by Terry Anastasiadis 3 weeks ago

1 comment

John-David Dalton commented on 17th March 2012: ∞

By spec (here and here) both == and === should perform the same number of steps when comparing like type values.

The point of this test is to show that even though there are micro differences there is no real world performance concern for using === over == as the lowest ops/sec are still in the millions of operations a second. You should use the correct operator for the job.