Run results for: js for in vs object.keys

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.170 Safari/537.36

Browser: Chrome 66

Operating system: Linux

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
for in	2.3 Ops/sec
object.keys	1.0 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) { if (obj.hasOwnProperty(key)) { console.log(key); } } }
object.keys
for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }