Run results for: Object.keys.length vs sum with for

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Goanna/4.8 Firefox/68.0 PaleMoon/29.2.0

Browser: Pale Moon (Firefox Variant) 29

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
_.isEmpty	185282.6 Ops/sec
Object.keys().length	376072.8 Ops/sec

Script Preparation code:

window.obj = {};

for (var i = 0, len = 100; i < len; i++) {
  obj['key' + i] = 'value' + i;
}

Tests:

_.isEmpty
let len = 0; for (const key in obj) { if (obj.hasOwnProperty(key)) { len++; } }
Object.keys().length
let len = Object.keys(window.obj).length;