Benchmark: JavaScript spread operator vs Object.assign performance fixed 4

Script Preparation code:

var firstObject = {
    sampleData: 'Hello world'
}
var secondObject2 = {
    moreData32: 'foo bar'
}
var secondObject3 = {
    moreData323232: 'foo bar'
}
var secondObject4 = {
    moreData32: 'foo bar'
}
var secondObject5 = {
    more32Data: 'foo bar'
}
var secondObject6 = {
    mo3232reData: 'foo bar'
}
var secondObject7 = {
    moreDat3232a: 'foo bar'
}

Tests:

Using the spread operator
const finalObject = { ...firstObject, ...secondObject2, ...secondObject3, ...secondObject4, ...secondObject5, ...secondObject6, ...secondObject7, };
Using Object.assign
const finalObject = Object.assign({},firstObject, secondObject2, secondObject3, secondObject4, secondObject5, secondObject6, secondObject7,);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Let's break down what is being tested in this benchmark.

**Benchmark Definition**

The benchmark measures the performance of two approaches to merge multiple objects into one:

1. **Spread Operator (`...`)**: This approach uses the spread operator, introduced in ECMAScript 2015, to create a new object by merging multiple source objects.
2. **Object.assign()**: This approach uses the `Object.assign()` method to merge multiple source objects into a target object.

**Options Compared**

The benchmark compares the performance of these two approaches on a set of identical input objects:

* `firstObject` is an initial object with a single property, `sampleData`, containing the string "Hello world".
* Six additional objects (`secondObject2` to `secondObject7`) are created, each adding more properties to `firstObject`.

**Pros and Cons**

* **Spread Operator**: Pros:
	+ Concise and readable syntax.
	+ Can be used to merge objects in a declarative way.
* Cons:
	+ May incur overhead due to the creation of temporary objects during merging.
	+ Not supported by older browsers (prior to Chrome 57).
* **Object.assign()**: Pros:
	+ Widely supported across modern browsers and Node.js versions.
	+ Can be used with arrays and other non-object inputs.
* Cons:
	+ Requires explicit calling of the `Object.assign()` method, which can add verbosity.

**Library and Special JS Feature/Syntax**

In this benchmark, no libraries are explicitly mentioned. However, it's worth noting that modern JavaScript engines (like V8 in Chrome) have built-in support for the spread operator (`...`).

No special JavaScript features or syntax are used beyond what is considered standard in ECMAScript.

**Other Alternatives**

If you need to merge objects and want alternatives to the spread operator or `Object.assign()`, consider:

* **Lodash's `_.merge()`**: A utility function for merging objects, providing more flexibility than the spread operator.
* **Array methods (`concat()`, `spread()`) with object wrapping**: While not as readable, these approaches can be used to merge objects into a new array or object.

Keep in mind that this benchmark is focused on comparing the performance of two specific approaches, and exploring alternative libraries or techniques might introduce additional complexity.

Related benchmarks:

JavaScript spread operator vs Object.assign performance fixed 4 (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):