Benchmark: JavaScript spread operator vs Object.assign performance vs merge mutation

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);
MergeObjects function
function mergeObjects(target, source) { for (const key in source) { if (typeof source[key] === 'object' && source[key] !== null) { if (!target[key] || typeof target[key] !== 'object' || target[key] === null) { target[key] = {}; } mergeObjects(target[key], source[key]); } else { target[key] = source[key]; } } } const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } mergeObjects(firstObject, secondObject)

Rendered benchmark preparation results:

Previous results

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Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

JavaScript spread operator vs Object.assign performance vs merge mutation (version: 0)