Run results for: for-in vs object.keys.for-loop vs object.keys.forEach

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36

Browser: Chrome 142

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 8 months ago

for-in

5K/s

Object.keys() -> for-loop

4K/s

Object.keys() -> for-each

3K/s

View exact numbers

Script Preparation code:

const OBJ = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};
const RUNS = 10_000;

Tests:

for-in
for (let i = 0; i < RUNS; i++) { const arr = []; for (const key in OBJ) { arr.push(key); } }
Object.keys() -> for-loop
for (let i = 0; i < RUNS; i++) { const arr = []; const keys = Object.keys(OBJ) for (let i = 0; i < keys.length; i++) { arr.push(keys[i]); }; }
Object.keys() -> for-each
for (let i = 0; i < RUNS; i++) { const arr = []; Object.keys(OBJ).forEach(key => arr.push(key)); }