Run results for: for-in vs object.keys (for)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36

Browser: Chrome 143

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 7 months ago

Object.keys

11/s

for-in

10/s

View exact numbers

Test name	Executions per second
✓ Object.keys	11 Ops/sec
for-in	10 Ops/sec

Script Preparation code:

var obj = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};

Tests:

for-in
for (var i=10000; i > 0; i--) { for (var key in obj) { console.log(key); } }
Object.keys
for (var i=10000; i > 0; i--) { const keys = Object.keys(obj); for (var j = 0; j < keys.length; j++) { console.log(keys[j]); } }