Run results for: index vs lastindexof (for right biased values) - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser: Chrome 97

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
lastIndexOf (near end)	623966.2 Ops/sec
indexOf (near end)	735155.3 Ops/sec
lastIndexOf (near head)	19166.1 Ops/sec
indexOf (near head)	13419535.0 Ops/sec

Script Preparation code:

var a = [...Array(20000)].map((x, i) => i);
var i = 0;

Tests:

lastIndexOf (near end)
var n = a.lastIndexOf(19000 + (i++ % 1000));
indexOf (near end)
var n = a.indexOf(19000 + (i++ % 1000));
lastIndexOf (near head)
var n = a.lastIndexOf(0 + (i++ % 1000));
indexOf (near head)
var n = a.indexOf(0 + (i++ % 1000));