Run results for: for loop: object vs map

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser: Chrome 103

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
for loop of Map	22922.3 Ops/sec
for loop of Object	2839.3 Ops/sec

Script Preparation code:

var mapData = [];
for (let i = 0; i < 10000; i++) {
  mapData.push([i, `object${i}`]);
}
var map = new Map(mapData);
                          
var obj = {};
for (let i = 0; i < 10000; i++) {
  obj[i] = `object${i}`;
}

Tests:

for loop of Map
let sum = 0; for (let [key, val] of map) { sum += key; }
for loop of Object
let sum = 0; for (let [key, val] of Object.entries(obj)) { sum += key; }

Run results for: for loop: object vs map

for loop of Map

for loop of Object