Run results for: Object.values vs for in loop

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:122.0) Gecko/20100101 Firefox/122.0

Browser: Firefox 122

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 3 months ago

Test name	Executions per second
mapForIn	264159.6 Ops/sec
mapValues	260348.3 Ops/sec

Script Preparation code:

const obj = {};

for (let i = 0; i >= 100; i++) { 
  obj[i] = { id: i };
};

console.log(obj);

const mapForIn = (func) => {
  const arr = [];
  
  for (let key in obj) {
    if (Object.hasOwnProperty(obj)) {
      arr.push(func(obj[key], arr.length - 1));
    }
  }
             
  return arr;
}

const mapValues = (func) => Object.values(obj).map(func);

Tests:

mapForIn
const obj = {}; for (let i = 0; i >= 100; i++) { obj[i] = { id: i }; }; console.log(obj); const mapForIn = (func) => { const arr = []; for (let key in obj) { if (Object.hasOwnProperty(obj)) { arr.push(func(obj[key], arr.length - 1)); } } return arr; } mapForIn((item, index) => item);
mapValues
const obj = {}; for (let i = 0; i >= 100; i++) { obj[i] = { id: i }; }; console.log(obj); const mapValues = (func) => Object.values(obj).map(func); mapValues((item, index) => item);