Run results for: map vs obj filling and accessing (string as key)

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 OPR/125.0.0.0

Browser: Opera 125

Operating system: Windows

Device Platform: Desktop

Date tested: 6 months ago

Accessing object

30/s

Filling object

28/s

Accessing map

22/s

Filling map

15/s

View exact numbers

Test name	Executions per second
✓ Accessing object	30 Ops/sec
Filling object	28 Ops/sec
Accessing map	22 Ops/sec
Filling map	15 Ops/sec

Script Preparation code:

const data = new Array(1000000)
	.fill(1)
	.map((item) => "somekeeeey-" + String(Math.floor(Math.random() * 10000)))

const map1 = new Map();
const map2 = {}

Tests:

Filling map
data.forEach((item) => { map1.set(item, { id: item, rand: Math.random() }); });
Filling object
data.forEach((item) => { map2[item] = { id: item, rand: Math.random() }; });
Accessing map
const aggr = [] data.forEach((item) => { aggr.push(map1.get(item)) });
Accessing object
const aggr = [] data.forEach((item) => { aggr.push(map2[item]); });