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: 5 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
};

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--) { Object.keys(obj).forEach(key => console.log(key)); }

Run results for: for-in vs object.keys

for-in

Object.keys