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

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

for .. of

71.4M/s

Object.keys

398K/s

Object.keys with extra array

364K/s

Object.entries without array

138K/s

Object.entries

138K/s

View exact numbers

Test name	Executions per second
✓ for .. of	71,408,832 Ops/sec
Object.keys	398,020 Ops/sec
Object.keys with extra array	363,528 Ops/sec
Object.entries without array	138,183 Ops/sec
Object.entries	137,639 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 = new Array();

for (let i = 0; i < 100; i++) {
	window.parentObj[makeid()] = { innerVal: 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]; } });
for .. of
const newObj = {}; for(const k of window.parentObj) { const i = window.parentObj[k]; if ((i % 2) === 0) { newObj[k] = i; } };