Info

Testing the performance impact of a capturing group vs. a non-capturing group inside a regex, also to see if .test() vs. .exec() affects the outcome.

Preparation code

<script>
  var regex_1 = /ab(cd)/g;
  var regex_2 = /ab(?:cd)/g;
  var test_str = "abcdjnksjdablkjnsabcdaslkd)A-s23-0kwasabkjabcd"; // 3 matches
  var tmp;
</script>

Test runner

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regex_1.lastIndex = 0; // reset regex in case browser caches it
tmp = regex_1.test(test_str);

regex_1.lastIndex = 0; // reset regex in case browser caches it
tmp = regex_1.exec(test_str);

regex_2.lastIndex = 0; // reset regex in case browser caches it
tmp = regex_2.test(test_str);

regex_2.lastIndex = 0; // reset regex in case browser caches it
tmp = regex_2.exec(test_str);

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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 Kyle Simpson on 21st August 2010
• Revision 2: published by cHao on 15th April 2012

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