Run results for: Object.entries vs for..in

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..in

18/s

Object.entries (for loop)

18/s

Object.entries (forEach)

17/s

View exact numbers

Test name	Executions per second
✓ for..in	18 Ops/sec
Object.entries (for loop)	18 Ops/sec
Object.entries (forEach)	17 Ops/sec

Script Preparation code:

var obj = {
	a: 1,
    b: 2,
	c: 3,
	d: 4,
	0: 'a',
  	1: 'b',
  	str: 'long string',
	nested: {
    	nested: 0
    },
	hello: 55.5
};
for (let i = 10; i < 10000; i++) { obj[""+i] = "test" }

Tests:

Object.entries (forEach)
Object.entries(obj).forEach((key, value) => console.log(key, value));
for..in
for (let key in obj) { if (obj.hasOwnProperty(key)) console.log(key, obj[key]); }
Object.entries (for loop)
for (let entries = Object.entries(obj), i = entries.length - 1, entry = entries[i]; i >= 0; entry = entries[i--]) { console.log(entry[0], entry[1]) }