Run results for: for-in vs object.keys

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 11_4 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) CriOS/69.0.3497.105 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 69

Operating system: iOS 11.4

Device Platform: Mobile

Date tested: 6 years ago

Test name	Executions per second
for-in	6.8 Ops/sec
Object.keys	5.7 Ops/sec

Script Preparation code:

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

AخA
 
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); 
  }
}

 
for (var i=10000; i > 0; i--) {  for (var key in obj) {      console.log(key);   }}

Object.keys
for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }
for (var i=10000; i > 0; i--) {
Object.keys(obj).forEach(key => console.log(key));
}

Run results for: for-in vs object.keys

for-in

Object.keys