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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.96 YaBrowser/20.4.0.3443 Yowser/2.5 Safari/537.36

Browser: Yandex Browser 20

Operating system: Mac OS X 10.14.6

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Using the spread operator	17770810.0 Ops/sec
Using Object.assign	4747118.0 Ops/sec
add	680403500.0 Ops/sec

Tests:

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

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

Using the spread operator

Using Object.assign

add