Run results for: ClassList has add or direct add

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:139.0) Gecko/20100101 Firefox/139.0

Browser: Firefox 139

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

check has and add class

17.7M/s

Direct add class

2.4M/s

View exact numbers

Test name	Executions per second
✓ check has and add class	17,712,532 Ops/sec
Direct add class	2,421,664 Ops/sec

HTML Preparation code:

<div class="el"></div>

Script Preparation code:

var el = document.querySelector('.el')

Tests:

check has and add class
!el.classList.contains('el') && el.classList.add('el') !el.classList.contains('el2') && el.classList.add('el2')
Direct add class
el.classList.add('el') el.classList.add('el2')