Run results for: iterate over map vs array-backed map

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser: Chrome 138

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 9 months ago

array-backed map

53.7M/s

map

18.9M/s

View exact numbers

Test name	Executions per second
✓ array-backed map	53,697,336 Ops/sec
map	18,945,658 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const map = new Map([[1,null],[2, null],[3, null],[4, null]])
const array = [1,2,3,4]
const mapWithArray = new Map([[1,null],[2, null],[3, null],[4, null]])
function getStructures() {
 return { map, array, mapWithArray } 
}

Tests:

map
const {map, array, mapWithArray} = getStructures() for (const [key, value] of map) { key; value; }
array-backed map
const {map, array, mapWithArray} = getStructures() for (const key of array) { key; mapWithArray.get(key) }