Run results for: Iterate over object

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36

Browser: Chrome 69

Operating system: Mac OS X 10.13.6

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
for..in with hasOwnProperty()	1139.4 Ops/sec
for..in without hasOwnProperty()	1901.9 Ops/sec
Object.keys() + Array.forEach()	1564.4 Ops/sec
Object.keys() + Array.for()	1890.2 Ops/sec

Script Preparation code:

var o = {};

for(var i=0; i<5000; i++) {
  o[i] = i;
}

Tests:

for..in with hasOwnProperty()
for (const key in o) { if (o.hasOwnProperty(key)) { const element = o[key]; } }
for..in without hasOwnProperty()
for (const key in o) { const element = o[key]; }
Object.keys() + Array.forEach()
const keys = Object.keys(o); keys.forEach((key)=>{ const element = o[key]; })
Object.keys() + Array.for()
const keys = Object.keys(o); const length = keys.length; for (let k = 0; k < length; k++) { const element = o[keys[k]]; }