Run results for: for-in vs object.keys true

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36

Browser: Chrome 93

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
for-in	1.2 Ops/sec
Object.keys	0.9 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--) { const keys = Object.keys(obj) for (let key of keys) { console.log(key); } }