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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:132.0) Gecko/20100101 Firefox/132.0

Browser: Firefox 132

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

for-in

2K/s

Object.keys

1K/s

View exact numbers

Test name	Executions per second
✓ for-in	2,209 Ops/sec
Object.keys	1,450 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) { const b = obj[key] } }
Object.keys
for (var i=10000; i > 0; i--) { const keys = Object.keys(obj) for (let i = 0; i < keys.length; i++) { const b = obj[keys[i]] } }