Run results for: Object.entries VS Object.keys VS Object.keys with extra array VS Object.entries without array

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_3_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/133.0.6943.33 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 133

Operating system: iOS 18.3.0

Device Platform: Mobile

Date tested: one year ago

Object.keys

141K/s

Object.entries

101K/s

Object.entries without array

99K/s

Object.keys with extra array

90K/s

View exact numbers

Test name	Executions per second
✓ Object.keys	141,011 Ops/sec
Object.entries	101,460 Ops/sec
Object.entries without array	99,393 Ops/sec
Object.keys with extra array	89,844 Ops/sec

Script Preparation code:

function makeid() {
  var text = "";
  var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

  for (var i = 0; i < 5; i++)
    text += possible.charAt(Math.floor(Math.random() * possible.length));

  return text;
}

window.parentObj = {};

for (let i = 0; i < 100; i++) {
	window.parentObj[makeid()] = makeid();
}

Tests:

Object.entries
const newObj = {}; Object.entries(window.parentObj).forEach(([k, v], i) => { if ((i % 2) === 0) { newObj[k] = v; } });
Object.keys
const newObj = {}; Object.keys(window.parentObj).forEach((k, i) => { if ((i % 2) === 0) { newObj[k] = window.parentObj[k]; } });
Object.keys with extra array
const newObj = {}; Object.keys(window.parentObj).forEach((k, i) => { const [extraK, v] = [k, window.parentObj[k]] if ((i % 2) === 0) { newObj[extraK] = v; } });
Object.entries without array
const newObj = {}; Object.entries(window.parentObj).forEach((keyAndVal, i) => { if ((i % 2) === 0) { newObj[keyAndVal[0]] = keyAndVal[1]; } });