Benchmark: Regex vs .indexOf vs .startsWith vs .substr

HTML Preparation code:

<div></div>

Script Preparation code:

window.regex = /^test/;
window.match = 'test';
var data = window.data = [];
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

function makeRandomString(len) {
  var text = "";
  for( var i=0; i < len; i++ ) {
    text += possible.charAt(getRandomInt(possible.length));
  }
  return text;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(getRandomInt(20)));
}

Tests:

Regex
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regex; while (x < TOTAL_STRINGS) { const str = data[x]; regex.test(str); x += 1; }
.indexOf
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; str.indexOf(match) === 0; x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
.indexOf

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 9 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:129.0) Gecko/20100101 Firefox/129.0

Browser/OS: Firefox 129 on Linux

View result in a separate tab

Test name	Executions per second
Regex	220.9 Ops/sec
.indexOf	4947.4 Ops/sec

Regex vs .indexOf vs .startsWith vs .substr (version: 11)

Testing some things

Comparing performance of: Regex vs .indexOf

Created: 7 years ago by: Registered User

Jump to the latest result

Regex

.indexOf

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A