Benchmark: JS Regex vs .startsWith vs .indexOf 2

HTML Preparation code:

<div></div>

Script Preparation code:

window.regexStart = /^test/;
window.regexEnd = /test$/;
window.match = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
window.matchLength = window.match.length;
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(2000)));
}

Tests:

startsWith
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.startsWith(match); x += 1; }
indexOf start
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; }
lastIndexOf
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var length = window.matchLength; while (x < TOTAL_STRINGS) { const str = data[x]; str.lastIndexOf(match, 0); x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
startsWith
indexOf start
lastIndexOf

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Windows

View result in a separate tab

indexOf start

7K/s

startsWith

803/s

lastIndexOf

233/s

View exact numbers

Test name	Executions per second
✓ indexOf start	7,218 Ops/sec
startsWith	803 Ops/sec
lastIndexOf	233 Ops/sec

JS Regex vs .startsWith vs .indexOf 2 (version: 1)

fork of https://www.measurethat.net/Benchmarks/Show/975/11/regex-vs-indexof-vs-startswith-vs-substr

Comparing performance of: `startsWith vs indexOf start vs lastIndexOf`

Created: one year ago by: Guest

Go to the latest result

startsWith

indexOf start

lastIndexOf

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

JS Regex vs .startsWith vs .indexOf 2 (version: 1)

fork of https://www.measurethat.net/Benchmarks/Show/975/11/regex-vs-indexof-vs-startswith-vs-substr

Comparing performance of: startsWith vs indexOf start vs lastIndexOf

Created: one year ago by: Guest

Go to the latest result

startsWith

indexOf start

lastIndexOf

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `startsWith vs indexOf start vs lastIndexOf`