Run results for: array.map() with spread vs for-loop

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser: Chrome 122

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 8 months ago

Test name	Executions per second
Object.fromEntries with spread	154.1 Ops/sec
for-loop and object (reuse object)	7519.6 Ops/sec
for-loop and object (creating temporary objects)	54.1 Ops/sec
for-loop and map	848.7 Ops/sec

Script Preparation code:

var entries = Object.entries({ ...Array.from(Array(10000).keys()) });

Tests:

Object.fromEntries with spread
const obj = Object.fromEntries([ ...entries.map((key, value) => [key, value]) ]);
for-loop and object (reuse object)
const obj = {}; for (const [key, value] of entries) { obj[key] = value; }
for-loop and object (creating temporary objects)
let obj = {}; for (const [key, value] of entries) { obj = { ...obj, [key]: value }; }
for-loop and map
const map = new Map(); for (const [key, value] of entries) { map.set(key, value); } const obj = Object.fromEntries(map);