Run results for: RegExp unnecessary matches implications

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/113.0.5672.69 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 113

Operating system: iOS 16.5

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
With unnecessary matches	2526798.0 Ops/sec
Without unnecessary matches	3325580.0 Ops/sec

Script Preparation code:

var matches = [
  'this_is_a_match',
  'another_match',
  'match_with_numbers_9',
  '100_200_300_400_500'
];

var no_matches = [
  'this_is_not_a-match',
  'another_no_match@',
  'no_match_with_numbers_9_*',
  '100_200_300_400_500_#'
];

Tests:

With unnecessary matches
var result_matches = matches.map((str) => /^[\w\d_]+$/.test(str)); var result_no_matches = no_matches.map((str) => /^[\w\d_]+$/.test(str));
Without unnecessary matches
var result_matches = matches.map((str) => /^\w+$/.test(str)); var result_no_matches = no_matches.map((str) => /^\w+$/.test(str));

Run results for: RegExp unnecessary matches implications

Check if having unnecessary matches in a regular expression has some performance implication

With unnecessary matches

Without unnecessary matches