Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
Run results for:
JavaScript spread operator vs Object.assign vs null-checked for-in loop performance
Measure the fastest way to merge objects, without mutation.
Go to the benchmark
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=619477" width="100%" height="500px"></iframe>
Run details:
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36
Browser:
Chrome 141
Operating system:
Mac OS X 10.15.7
Device Platform:
Desktop
Date tested:
6 months ago
Test name
Executions per second
Using the spread operator
34447756.0 Ops/sec
Using Object.assign
26264912.0 Ops/sec
Using For-In loop
63454140.0 Ops/sec
Using For-In loop with type checks
27765372.0 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 For-In loop
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = {} for (let key in firstObject) { finalObject[key] = firstObject[key]; } for (let key in secondObject) { finalObject[key] = secondObject[key]; }
Using For-In loop with type checks
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = {} if (firstObject != null) { for (let key in firstObject) { if (Object.prototype.hasOwnProperty.call(firstObject, key)) { finalObject[key] = firstObject[key]; } } } if (secondObject != null) { for (let key in secondObject) { if (Object.prototype.hasOwnProperty.call(secondObject, key)) { finalObject[key] = secondObject[key]; } } }