Run results for: Array check key

Run details:

User agent: Mozilla/5.0 (Linux; Android 12; Redmi 5 Plus) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 103

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
Undefined	226962.1 Ops/sec
In	288512.5 Ops/sec

Script Preparation code:

var arr = [];
for (let i = 0; i < 1000; i++) arr[i] = i;

function randomKey() {
    return Math.floor(Math.random() * 2000);
}

Tests: