Run results for: NodeList For vs Foreach

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser: Firefox 132

Operating system: Ubuntu

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

forEach

3.3M/s

Default For

1K/s

For with length caching

1K/s

View exact numbers

Test name	Executions per second
✓ forEach	3,321,344 Ops/sec
Default For	1,272 Ops/sec
For with length caching	1,252 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'); }