Run results for: for-in vs object.keys

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; MAR-LX3A Build/HUAWEIMAR-L03A;) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/81.0.4044.138 Mobile Safari/537.36

Browser: Chrome Mobile 81

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
for-in	0.4 Ops/sec
Object.keys	0.4 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