Run results for: for-in vs object.keys + for

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.86 YaBrowser/20.8.0.893 Yowser/2.5 Safari/537.36

Browser: Yandex Browser 20

Operating system: Mac OS X 10.15.6

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
for-in	1109500.0 Ops/sec
Object.keys	914853.4 Ops/sec

Script Preparation code:

var obj = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};

AخA
 
var obj = {  'a': 1,  'b': 1,  'c': 1,  'd': 1,  'e': 1,  'f': 1,  'g': 1};

Tests:

for-in

const result = [];
for (var key in obj) {
  result.push(key, obj[key]);
}

​x
 
const result = [];for (var key in obj) {  result.push(key, obj[key]);}​

Object.keys

const result = [];
const keys = Object.keys(obj);
for (let i = 0; i < keys.length; i++) {
  const key = keys[i];
  result.push(key, obj[key]);
}

 
const result = [];const keys = Object.keys(obj);for (let i = 0; i < keys.length; i++) {  const key = keys[i];  result.push(key, obj[key]);}