Run results for: for-in vs object.keys

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) snap Chromium/73.0.3683.75 Chrome/73.0.3683.75 Safari/537.36

Browser: Chromium 73

Operating system: Linux

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
for-in	41.7 Ops/sec
Object.keys	26.2 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)); }