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

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 14_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 14

Operating system: iOS 14.0

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
Using the spread operator	1361069.0 Ops/sec
Using Object.assign	2432187.0 Ops/sec
Using Object.assign no mutation	2073790.0 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);
Using Object.assign no mutation
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);