Run results for: For in vs Object.keys.forEach

Run details:

User agent: Mozilla/5.0 (Linux; arm_64; Android 14; ASUS_AI2202) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.6367.26 YaBrowser/24.6.6.26.00 SA/3 Mobile Safari/537.36

Browser: Yandex Browser 24

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
For In	1043.1 Ops/sec
Object keys forEach	1041.3 Ops/sec

Script Preparation code:

var obj = new Object()
var keys = (new Array(100)).fill(0).map((x, i) => { return i + 1 })
keys.forEach((x) => { obj['prop' + x] = x })

Tests:

For In
for (var key in obj) { if (obj.hasOwnProperty(key)) console.log(obj[key]) }
Object keys forEach
Object.keys(obj).forEach(key => console.log(obj[key]))

Run results for: For in vs Object.keys.forEach

For In

Object keys forEach