Benchmark: JavaScript spread operator vs Object.assign performance v3

Tests:

Using the spread operator
const secondObject = {sampleData: 'Hello world', moreData: 'foo bar' } const finalObject = { ...secondObject };
Using Object.assign
const secondObject = {sampleData: 'Hello world', moreData: 'foo bar' } const finalObject = Object.assign({}, secondObject);

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:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using the spread operator	92527152.0 Ops/sec
Using Object.assign	38335196.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Benchmark Overview**

The benchmark, hosted on MeasureThat.net, is designed to compare the performance of two approaches for creating shallow copies of objects in JavaScript: using the spread operator (`...`) and `Object.assign()` with an empty object `{}`.

**Test Cases**

There are only two test cases:

1. **Using the Spread Operator**
```javascript
const secondObject = { sampleData: 'Hello world', moreData: 'foo bar' }
const finalObject = { ...secondObject }
```
This test case creates a shallow copy of `secondObject` using the spread operator (`...`). The resulting object, `finalObject`, will have the same properties as `secondObject`.

2. **Using Object.assign**
```javascript
const secondObject = { sampleData: 'Hello world', moreData: 'foo bar' }
const finalObject = Object.assign({}, secondObject)
```
This test case creates a shallow copy of `secondObject` using the `Object.assign()` method with an empty object `{}` as the target.

**Options Compared**

The benchmark is comparing two options:

* Using the spread operator (`...`)
* Using `Object.assign()` with an empty object `{}`

**Pros and Cons**

1. **Using the Spread Operator**
	* Pros:
		+ Simple and concise syntax
		+ Works well for shallow objects
	* Cons:
		+ Can be slower than other methods for very large objects (due to the overhead of creating a new array)
2. **Using Object.assign**
	* Pros:
		+ Can be faster than the spread operator for very large objects
	* Cons:
		+ Requires an empty object as the target, which can be unnecessary
		+ Less intuitive syntax compared to the spread operator

**Library Usage**

Neither test case uses any external libraries.

**Special JS Feature/Syntax**

There is no specific JavaScript feature or syntax being tested in these benchmark cases. The focus is on comparing two simple approaches for creating shallow copies of objects.

**Other Alternatives**

If you need to create a deep copy of an object, the spread operator may not be sufficient. In such cases, you can use the `JSON.parse(JSON.stringify(object))` method or libraries like Lodash's `cloneDeep()` function.

For more complex scenarios, you might consider using libraries like Object.assign() alternatives like `lodash.clone()` or `immediate-assign`.

Keep in mind that these benchmarks are designed to compare simple approaches for shallow object copying. In real-world applications, you may encounter more complex use cases that require different solutions.

Related benchmarks:

JavaScript spread operator vs Object.assign performance v3 (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

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