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

Run details:

User agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:95.0) Gecko/20100101 Firefox/95.0

Browser: Firefox 95

Operating system: Fedora

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
lastIndexOf (near end)	870581.0 Ops/sec
indexOf (near end)	27161.1 Ops/sec
lastIndexOf (near head)	24040.2 Ops/sec
indexOf (near head)	972110.4 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));

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