Run results for: JavaScript spread operator vs object update performance

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 26_0_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/141.0.7390.96 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 141

Operating system: iOS 26.0.1

Device Platform: Mobile

Date tested: 6 months ago

Test name	Executions per second
Using update	548855040.0 Ops/sec
Using Object.assign	33952444.0 Ops/sec

Tests:

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

Run results for: JavaScript spread operator vs object update performance

Using update

Using Object.assign