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

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_6_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.6 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.6.2

Device Platform: Mobile

Date tested: 11 months ago

Using Object.assign

12.9M/s

Using the spread operator

6.9M/s

View exact numbers

Test name	Executions per second
✓ Using Object.assign	12,945,761 Ops/sec
Using the spread operator	6,932,536 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);