Run results for: for-in vs Object.keys()

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36

Browser: Chrome 87

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 3 years ago

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 forEach
for (var i=10000; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }
Object.keys for loop
for (var i=10000; i > 0; i--) { const keys = Object.keys(obj); for (let i = 0; i < keys.length; i++) { console.log(obj[keys[i]]); } }