Run results for: for-in vs object.keys

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.70 Safari/537.36

Browser: Chrome 78

Operating system: Mac OS X 10.15.0

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
for-in	1.1 Ops/sec
Object.keys	0.8 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 (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));
}