Run results for: Add item to array: push vs spread vs assign:

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:148.0) Gecko/20100101 Firefox/148.0

Browser: Firefox 148

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 5 months ago

Direct assign an item to an initialized array

429K/s

Push item to an array

402K/s

Append an item by spread

443/s

View exact numbers

Test name	Executions per second
✓ Direct assign an item to an initialized array	428,813 Ops/sec
Push item to an array	401,824 Ops/sec
Append an item by spread	443 Ops/sec

Script Preparation code:

window.MAX_SIZE = 1000;

Tests:

Push item to an array
const items = []; for (let i = 0; i < MAX_SIZE; i++) { items.push(i); }
Append an item by spread
let items = []; for (let i = 0; i < MAX_SIZE; i++) { items = [...items, i]; }
Direct assign an item to an initialized array
const items = new Array(MAX_SIZE); for (let i = 0; i < MAX_SIZE; i++) { items[i] = i; }