Run results for: Map vs preallocation

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: 11 months ago

Preallocation

646/s

Map

117/s

View exact numbers

Test name	Executions per second
✓ Preallocation	646 Ops/sec
Map	117 Ops/sec

Script Preparation code:

var array = new Array(1000000).fill(0);

Tests:

Map
const array2 = array.map((item, index) => index);
Preallocation
const array2 = new Array(1000000).fill(0); for (let i = 0; i < array2.length; i++) array2[i] = i;