Run results for: NodeList For vs Foreach

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.1.2 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

forEach

9.8M/s

For with length caching

10K/s

Default For

5K/s

View exact numbers

Test name	Executions per second
✓ forEach	9,839,282 Ops/sec
For with length caching	10,218 Ops/sec
Default For	5,099 Ops/sec

Script Preparation code:

var div = document.createElement('div');
for (let i = 0; i < 1000; i++) {
    div.insertAdjacentHTML('beforeend', `<span>span-${i}<span>`);
}

var list = div.querySelectorAll('span');

Tests:

Default For
for(let i = 0; i < list.length; i++) { list[i].setAttribute('tabindex', '-1'); }
For with length caching
list.forEach(item =>{ item.setAttribute('tabindex', '-1'); });
forEach
for(let i = 0, lenght = list.lenght ; i < length; i++) { list[i].setAttribute('tabindex', '-1'); }