Run results for: Object spread vs new Map vs Object assign with complex data

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.0

Device Platform: Mobile

Date tested: one year ago

new Map

720K/s

Object spread

231K/s

Object assign

202K/s

View exact numbers

Test name	Executions per second
✓ new Map	719,920 Ops/sec
Object spread	231,436 Ops/sec
Object assign	201,514 Ops/sec

Script Preparation code:

var data = new Array(1000000).fill(undefined).map((_,i) => i)
var obj = data.reduce((obj, idx) => {obj['idx' + Date.now()] = {name: 'Name: ' + Date.now(), age: idx}; return obj}, {});
var map = new Map(Object.entries(obj));

Tests:

Object spread
var copy = {...obj}
new Map
var copy = new Map(map)
Object assign
var copy = Object.assign({}, obj)