Run results for: for-in Object.hasOwn vs for-of Object.keys

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/113.0

Browser: Firefox 113

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
for-in Object.hasOwn	0.6 Ops/sec
for-of Object.keys	0.6 Ops/sec

Script Preparation code:

var obj = {
  a: 1,
  b: 1,
  c: 1,
  d: 1,
  e: 1,
  f: 1,
  g: 1,
  h: 1,
  i: 1,
  j: 1,
  k: 1,
  l: 1,
  m: 1,
  n: 1,
  o: 1,
  p: 1,
  q: 1,
  r: 1,
  s: 1,
  t: 1,
  u: 1,
  v: 1,
  w: 1,
  x: 1,
  y: 1,
  z: 1
};

Tests:

for-in Object.hasOwn
for (let i = 10000; i > 0; i--) { for (const key in obj) { if (!Object.hasOwn(obj, key)) { continue } console.log(key); } }
for-of Object.keys
for (let i = 10000; i > 0; i--) { for (const key of Object.keys(obj)) { console.log(key) } }