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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 arr = ['a', 'b', 'c', 'd']
</script>

Setup JS

Teardown JS

Test cases

Test #1

Title *

Async

Code *var foo = 'a' + 'b' + 'c' + 'd';

Test #2

Title *

Async

Code *

var foo = 'a';
foo += 'b';
foo += 'c';
foo += 'd';

Test #3

Title *

Async

Code *

var foo = 'a';
foo = foo + 'b';
foo = foo + 'c';
foo = foo + 'd';

Test #4

Title *

Async

Code *var foo = arr.join('');

Test #5

Title *

Async

Code *

var foo = 'a';
foo += 'b' + 'c' + 'd';

Test #6

Title *

Async

Code *

function concat(arr) {
  len = arr.length;
  for (s = "", i = 0; i < len; s += arr[i], i++);
  return s;
}

var foo = concat(arr);

Test #7

Title *

Async

Code *var foo = 'a' + 'b' + 'c' + 'd' + 'e';

Test #8

Title *

Async

Code *var foo = 'abcd';