const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = {
firstObject,
secondObject
};
const finalObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
Object.assign(finalObject, secondObject);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Using the spread operator | |
Using Object.assign |
Test name | Executions per second |
---|---|
Using the spread operator | 2482476.0 Ops/sec |
Using Object.assign | 5658880.0 Ops/sec |
Let's dive into explaining the benchmark.
Benchmark Overview
The provided JSON represents a JavaScript microbenchmark on MeasureThat.net, comparing the performance of two approaches for merging objects: using the spread operator (...
) and Object.assign()
. The test is designed to measure which approach is more efficient without unnecessary assignments.
Options Compared
Two options are being compared:
...
):Object.assign()
:Pros and Cons of Each Approach
Both approaches have their trade-offs:
Object.assign()
offers an established, widely supported method for merging objects, potentially with optimized internal implementation, but requires explicit checking for object existence or assignment.Library Used
There is no library explicitly mentioned in the provided JSON. However, it's worth noting that Object.assign()
has been a built-in method in JavaScript since ECMAScript 2015 (ES6), making it widely supported across different browsers and environments.
Special JS Feature/Syntax
The benchmark utilizes the spread operator (...
), which is a relatively new feature introduced in ECMAScript 2018 (ES2018). The spread operator allows you to expand an array or object into multiple arguments or merge objects using the ...
syntax. This feature has become widely supported across modern browsers and environments.
Alternatives
If you're interested in exploring alternative approaches for merging objects, consider the following options:
Object.create()
and then assign properties to it.Array.prototype.concat()
and then convert the result back to an object.Keep in mind that these alternatives might not be as concise or readable as the spread operator or Object.assign()
, but they can provide a deeper understanding of how merging objects works under the hood.