Run results for: Object filter mapping

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser: Chrome 125

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Object.entries	82606.6 Ops/sec
Object.key	133735.6 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
Object.fromEntries(Object.entries(window.parentObj).filter(([k, v], i) => ((i % 2) === 0)));
Object.key
Object.keys(window.parentObj).reduce((acc, k, i) => { if ((i % 2) === 0) { acc[k] = window.parentObj[k]; } return acc }, {});

Run results for: Object filter mapping

benchmark comparing the perf of creating a new object by filter out entries

Object.entries

Object.key