Run results for: Object vs Map

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser: Chrome 128

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Map read

17K/s

Object read

12K/s

Map set

1K/s

Object set

972/s

View exact numbers

Test name	Executions per second
✓ Map read	17,003 Ops/sec
Object read	11,824 Ops/sec
Map set	1,291 Ops/sec
Object set	972 Ops/sec

Script Preparation code:

function randomString()
{
    var text = "";
    var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    for( var i=0; i < 5; i++ )
        text += possible.charAt(Math.floor(Math.random() * possible.length));

    return text;
}

const map = new Map();
const obj = {};

const map2 = new Map();
const obj2 = {};

for (let i = 0; i < 1000; i++) {
   const key = randomString();
   const val = randomString();
   map2.set(key,val);
   obj2[key] = val;
}

Tests:

Map set
for (let i=0; i < 1000; i++) { const key = randomString(); const val = randomString(); map.set(key,val); }
Object set
for (let i=0; i < 1000; i++) { const key = randomString(); const val = randomString(); obj[key] = val; }
Map read
for (let key of map2.keys()) { const val = map2.get(key); }
Object read
for (let key in obj2) { const val = obj2[key]; }