Run results for: test children matches vs classList vs querySelectorAll vs getElementsByClassName

Run details:

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser: Firefox 115

Operating system: Windows 8.1

Device Platform: Desktop

Date tested: 2 months ago

Test name	Executions per second
matches	4542.7 Ops/sec
classList	5532.7 Ops/sec
className	5555.3 Ops/sec
querySelectorAll	33463.0 Ops/sec
getElementsByClassName	1041310656.0 Ops/sec

HTML Preparation code:

<div id="test"></div>

Script Preparation code:

const count = 1000;
const holder = document.getElementById('test');

for (let i = 0; i < count; i++) {
   let elem = document.createElement('div');
   elem.classList.add(0|Math.random()*2 ? 'foo' : 'bar');
   holder.appendChild(elem);
}

Tests:

matches
const result = Array.from(holder.children).filter((node) => node.matches('.foo'));
classList
const result = Array.from(holder.children).filter((node) => node.classList.contains('foo'));
className
const result = Array.from(holder.children).filter((node) => node.className.includes('foo'));
querySelectorAll
const result = holder.querySelectorAll(':scope > .foo');
getElementsByClassName
const result = holder.getElementsByClassName('foo');

Run results for: test children matches vs classList vs querySelectorAll vs getElementsByClassName

matches

classList

className

querySelectorAll

getElementsByClassName