Run results for: JavaScript spread operator vs Object.assign performance

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/121.0.6167.138 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 121

Operating system: iOS 17.3

Device Platform: Mobile

Date tested: 2 years ago

Using the spread operator

12.3M/s

Using Object.assign

8.4M/s

View exact numbers

Test name	Executions per second
✓ Using the spread operator	12,328,763 Ops/sec
Using Object.assign	8,375,466 Ops/sec

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(firstObject, secondObject);