Benchmark: JavaScript spread operator vs Object.assign performance --UPDATE

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(Object.assign({}, firstObject), 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

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what's being tested.

The benchmark is designed to compare the performance of two approaches: using the spread operator (`...`) and `Object.assign()` in JavaScript. The test case consists of three objects:

1. `firstObject` with a single property `sampleData`.
2. `secondObject` with a single property `moreData`.

Two different final object creations are compared:

**Using the spread operator**

The benchmark definition code shows how to create a new object using the spread operator (`...`). The syntax is as follows:
```javascript
const finalObject = { ...firstObject, ...secondObject };
```
This creates a new object with all properties from `firstObject` and `secondObject`.

**Using Object.assign()**

The benchmark definition code also shows how to create a new object using `Object.assign()`. The syntax is as follows:
```javascript
const finalObject = Object.assign(Object.assign({}, firstObject), secondObject);
```
This creates a new object by merging `firstObject` and `secondObject`, starting with an empty object (`{}`).

**Comparison**

The benchmark measures the performance difference between these two approaches. The test cases aim to understand which method is faster and more efficient.

**Pros and Cons:**

* **Using the spread operator:**
	+ Pros:
		- Concise syntax.
		- Easy to read and write.
		- Can be used with arrays as well (e.g., ` [...firstObject, ...secondObject]`).
	+ Cons:
		- Not widely supported in older browsers.
		- May have performance implications due to the object creation process.
* **Using Object.assign():**
	+ Pros:
		- Wide support across modern browsers and engines.
		- Well-established syntax.
		- Can be used for merging objects with multiple levels of nesting.
	+ Cons:
		- Less concise syntax compared to the spread operator.

**Library and Special Features:**

There are no specific libraries mentioned in the benchmark definition. However, it's worth noting that `Object.assign()` is a built-in JavaScript method.

No special JavaScript features or syntax are used beyond what's described in the benchmark definition.

**Alternative Approaches:**

Other approaches to merge objects in JavaScript include:

1. Using the `concat` method:
```javascript
const finalObject = Object.concat({}, firstObject, secondObject);
```
2. Using the `merge` function from a library like Lodash (not shown in the benchmark):
```javascript
const _ = require('lodash');
const finalObject = _.merge({}, firstObject, secondObject);
```
3. Using a custom implementation of object merging.

Keep in mind that each approach has its pros and cons, and the choice ultimately depends on your specific use case, performance requirements, and personal preference.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:67.0) Gecko/20100101 Firefox/67.0

Browser/OS: Firefox 67 on Linux

View result in a separate tab

Test name	Executions per second
Using the spread operator	3324285.8 Ops/sec
Using Object.assign	2990325.2 Ops/sec

Related benchmarks:

JavaScript spread operator vs Object.assign performance --UPDATE (version: 0)

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

Created: 5 years ago by: Registered User

Jump to the latest result

Using the spread operator

Using Object.assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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