Benchmark: Object loops: for...in vs Object.keys+forEach (ES5) vs for...of (ES6) vs Object.entries (ES8)

Script Preparation code:

var obj = {};
for (let i = 0; i < 1000; i++) {
  obj['abc_' + i] = i;
}

function foo(bar) {
  return bar * 2 * 2;
}

Tests:

for...in
for (const key in obj) { if (obj.hasOwnProperty(key)) foo(obj[key]); }
Object.keys+forEach (ES5)
Object.keys(obj).forEach(function(key) { foo(obj[key]); });
for...of - keys (ES6)
for (const key of Object.keys(obj)) { foo(obj[key]); }
for...of - values (ES6)
for (const value of Object.values(obj)) { foo(value); }
for...of - entries (ES8)
for (const [key, value] of Object.entries(obj)) { foo(value); }
Object.entries (ES8)
Object.entries(obj).forEach(function(key, value) { foo(value); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for...in
Object.keys+forEach (ES5)
for...of - keys (ES6)
for...of - values (ES6)
for...of - entries (ES8)
Object.entries (ES8)

Fastest: N/A

Slowest: N/A

ⓘ Get performance results from real users on your website with Request Metrics.

Website Performance Monitoring by Request Metrics

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Linux; Android 14; SM-S928B) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.149 Mobile Safari/537.36 OPR/81.6.4292.79147

Browser/OS: Opera Mobile 81 on Android

View result in a separate tab

Test name	Executions per second
for...in	5460.6 Ops/sec
Object.keys+forEach (ES5)	8041.0 Ops/sec
for...of - keys (ES6)	7939.3 Ops/sec
for...of - values (ES6)	7061.0 Ops/sec
for...of - entries (ES8)	5888.1 Ops/sec
Object.entries (ES8)	5880.6 Ops/sec

Object loops: for...in vs Object.keys+forEach (ES5) vs for...of (ES6) vs Object.entries (ES8) (version: 7)

Comparing performance of: for...in vs Object.keys+forEach (ES5) vs for...of - keys (ES6) vs for...of - values (ES6) vs for...of - entries (ES8) vs Object.entries (ES8)

Created: 5 years ago by: Registered User

Jump to the latest result

for...in

Object.keys+forEach (ES5)

for...of - keys (ES6)

for...of - values (ES6)

for...of - entries (ES8)

Object.entries (ES8)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A