Run results for: foreach: object keys vs object entries vs for...in

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser: Chrome 140

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 10 months ago

object with keys

76K/s

for...in

57K/s

object with entries 2

34K/s

object with entries 1

33K/s

View exact numbers

Test name	Executions per second
✓ object with keys	75,953 Ops/sec
for...in	56,667 Ops/sec
object with entries 2	33,874 Ops/sec
object with entries 1	33,172 Ops/sec

Script Preparation code:

var obj = {};
const TXT = "ASDFASFASDFASDFSADFASDFASDFSDAFSDFASDFASDFASDFASDF";

const newObj = {};

for (i = 0; i < 10000; ++i) {
  obj[i] = `${i} ${TXT}`;
}

Tests:

object with keys
Object.keys(obj).forEach( (key) => { newObj[key] = obj[key]; } );
object with entries 1
Object.entries(obj).forEach( (entry) => { newObj[entry.key] = entry.value; } );
object with entries 2
Object.entries(obj).forEach( ([key, value]) => { newObj[key] = value; } );
for...in
for (const key in obj) { newObj[key] = obj[key] }