Run results for: JS lastIndexOf vs indexOf

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36 Edg/137.0.0.0

Browser: Chrome 137

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Array.lastIndexOf

42.4M/s

Array.indexOf

6K/s

View exact numbers

Test name	Executions per second
✓ Array.lastIndexOf	42,432,568 Ops/sec
Array.indexOf	5,619 Ops/sec

Script Preparation code:

var str = '';
var i = 0;

while (i <= 1E5) str += `${i++}`;

Tests: