Run results for: JS lastIndexOf vs indexOf

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:142.0) Gecko/20100101 Firefox/142.0

Browser: Firefox 142

Operating system: Windows

Device Platform: Desktop

Date tested: 10 months ago

Array.lastIndexOf

38.7M/s

Array.indexOf

20K/s

View exact numbers

Test name	Executions per second
✓ Array.lastIndexOf	38,725,444 Ops/sec
Array.indexOf	20,020 Ops/sec

Script Preparation code:

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

Tests: