Info

Comparison between the different ways of checking if a value is an array.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var A = [1, 2, 3, 4, 5],
    B = ['a', 'b', 'c', 'd', 'e'],
    C = [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]];
  };
</script>

Test runner

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

Java applet disabled.

A instanceof Array ? true : false;

B instanceof Array ? true : false;

C instanceof Array ? true : false;

Array.isArray(A) ? true : false;

Array.isArray(B) ? true : false;

Array.isArray(C) ? true : false;

A.constructor === Array ? true : false;

B.constructor === Array ? true : false;

C.constructor === Array ? true : false;

toString.call(A) === "[object Array]" ? true : false;

toString.call(B) === "[object Array]" ? true : false;

toString.call(C) === "[object Array]" ? true : false;

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 Brian Jemilo II on 29th October 2014
• Revision 2: published by Artur Raczyński on 13th November 2014
• Revision 3: published on 18th November 2014
• Revision 4: published on 24th November 2014
• Revision 5: published by Ezra Olubi on 27th November 2014
• Revision 6: published by Nikos M. on 15th December 2014
• Revision 7: published by Itsik Avidan on 17th December 2014
• Revision 8: published by me on 23rd January 2015
• Revision 9: published on 5th February 2015
• Revision 10: published on 25th February 2015
• Revision 11: published on 3rd March 2015
• Revision 15: published on 13th March 2015
• Revision 16: published on 20th March 2015
• Revision 17: published on 16th April 2015
• Revision 18: published on 17th April 2015
• Revision 19: published by ZAlexz on 23rd May 2015
• Revision 20: published by dalisoft on 12th June 2015
• Revision 21: published by dalisoft on 13th June 2015
• Revision 22: published by Mario DE WEERD on 4th August 2015

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