Run results for: for-in vs object.keys

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36

Browser: Chrome 64

Operating system: Mac OS X 10.13.3

Device Platform: Other

Date tested: 2024 years ago

Test name	Executions per second
for-in	13.0 Ops/sec
Object.keys	8.3 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=1000; i > 0; i--) { for (var key in obj) { console.log(key); } }
Object.keys
for (var i=1000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }