Benchmark: JavaScript spread operator vs Object.assign performance vs Adding to object one

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);
Add to first
const firstObject = { sampleData: 'Hello world' } firstObject.moreData = 'foo bar'

Rendered benchmark preparation results:

Previous results

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Windows

Add to first

163.8M/s

Using the spread operator

32.6M/s

Using Object.assign

30.3M/s

View exact numbers

JavaScript spread operator vs Object.assign performance vs Adding to object one (version: 1)