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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

Test case details

Title *

Description
(Markdown syntax is allowed)

Preparation Code

Preparation HTML
(this will be inserted in the <body> of a valid HTML5 document in standards mode)
(useful when testing DOM operations or including libraries)

<script>
  var str = 'string';
  var barr = ['this', ' is', ' a', str, ' to', ' test', ' if', ' there', ' is', ' any', ' difference', ' between', ' concat', ' and', ' join'];
  var sarr = ['this', ' is', ' a', str];
</script>

Setup JS

Teardown JS

Test cases

Test #1

Title *

Async

Code *

var a = 'this' + ' is' + ' a' + str + ' to' + ' test' + ' if' + ' there' + ' is' + ' any' + ' difference' + ' between' + ' concat' + ' and' + ' join';

Test #2

Title *

Async

Code *var a = barr.join('');

Test #3

Title *

Async

Code *var a = 'this' + ' is' + ' a' + str;

Test #4

Title *

Async

Code *var a = sarr.join('');

Test #5

Title *

Async

Code *

var str = '';
for (var i = 0; i < barr.length; i++) {
  str += barr[i];
}

Test #6

Title *

Async

Code *

['this', ' is', ' a', str, ' to', ' test', ' if', ' there', ' is', ' any', ' difference', ' between', ' concat', ' and', ' join'].join('');

Test #7

Title *

Async

Code *['this', ' is', ' a', str].join('');

Test #8

Title *

Async

Code *

(new Array('this', ' is', ' a', str, ' to', ' test', ' if', ' there', ' is', ' any', ' difference', ' between', ' concat', ' and', ' join')).join("");