Benchmark: for-in vs object.keys (many keys)

Script Preparation code:

var obj = Object.fromEntries(Array.from({
    length: 1000
}, (_, i) => [i.toString(), i]));

Tests:

for-in
for (let i=10; i > 0; i--) { for (let key in obj) console.log(key); }
Object.keys
for (let i=10; i > 0; i--) { for(let key of Object.keys(obj)) console.log(key); }

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

for-in

28/s

Object.keys

23/s

Fastest: for-in (1.2x faster)

View exact numbers

✓ for-in: 28 ops/sec
• Object.keys: 23 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-in
Object.keys

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 14 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36 Edg/150.0.0.0

Browser/OS: Chrome 150 on Windows

View result in a separate tab

for-in

24/s

Object.keys

23/s

View exact numbers

Test name	Executions per second
✓ for-in	24 Ops/sec
Object.keys	23 Ops/sec

for-in vs object.keys (many keys) (version: 1)

Comparing performance of: `for-in vs Object.keys`

Created: one year ago by: Guest

Go to the latest result

for-in

Object.keys

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

for-in vs object.keys (many keys) (version: 1)

Comparing performance of: for-in vs Object.keys

Created: one year ago by: Guest

Go to the latest result

for-in

Object.keys

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `for-in vs Object.keys`