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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36

Browser: Chrome 114

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 11 months ago

Test name	Executions per second
Push item to an array	9688.7 Ops/sec
Append an item by spread	1198.9 Ops/sec
Direct assign an item to an initialized array	10073.2 Ops/sec
Direct assign an item to an empty array	9743.5 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; }
Direct assign an item to an empty array
const items = new Array(); for (let i = 0; i < MAX_SIZE; i++) { items[i] = i; }