Run results for: CSS Variable swaps - style.setProperty vs style.cssText vs style vs Object.assign vs setAttribute vs classList

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser: Chrome 130

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

setAttribute

1K/s

classList

785/s

Object.assign

757/s

style.setProperty

422/s

style.cssText

347/s

style

265/s

View exact numbers

Test name	Executions per second
✓ setAttribute	1,046 Ops/sec
classList	785 Ops/sec
Object.assign	757 Ops/sec
style.setProperty	422 Ops/sec
style.cssText	347 Ops/sec
style	265 Ops/sec

HTML Preparation code:

<style>
  :root {
  	--test-color: 'red';
  }
  
  .test {
  	color: var(--test-color);
  }
  
  .test-blue {
  	--test-color: 'blue';
  }
  
</style>

<div id="test"></div>

Script Preparation code:

el = document.getElementById("test");

Tests:

style.setProperty
let i = 0; while (i < 10000) { el.style.setProperty("--test-color","blue"); i++; }
style.cssText
let i = 0; while (i < 10000) { el.style.cssText = "--test-color:blue;"; i++; }
style
let i = 0; while (i < 10000) { el.style = "--test-color:blue;"; i++; }
Object.assign
let style = { "--test-color": 'blue' }; let i = 0; while (i < 10000) { Object.assign(el.style, style); i++; }
setAttribute
let i = 0; while (i < 10000) { el.setAttribute('style',"--test-color:blue;"); i++; }
classList
let i = 0; while (i < 10000) { el.classList.add('test-blue'); i++; }