Benchmark: $.extend() vs Object.assign()

HTML Preparation code:

<script type="text/javascript" src="https://code.jquery.com/jquery-3.4.1.min.js"></script>
<div id="testThisId"></div>

Tests:

$.extend()
var target = { a: 1, b: 2 }; var source = { b: 4, c: 5 }; var returnedTarget = $.extend(target, source);
Object.assign()
var target = { a: 1, b: 2 }; var source = { b: 4, c: 5 }; var returnedTarget = Object.assign(target, source);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
$.extend()
Object.assign()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Test name	Executions per second
$.extend()	5521735.0 Ops/sec
Object.assign()	6401653.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**What is being tested?**

MeasureThat.net is testing two different methods for merging objects: `$.extend()` and `Object.assign()`. The benchmark is designed to compare the performance of these two approaches.

**Options compared:**

* `$.extend()`: a method provided by jQuery that merges one or more source objects into an existing target object.
* `Object.assign()`: a built-in JavaScript method that merges all enumerable own properties of one or more source objects into an existing target object.

**Pros and Cons:**

* **$.extend():**
	+ Pros:
		- Easy to use, especially for those familiar with jQuery.
		- Can be used to merge multiple objects at once using the `$.extend()` method's array syntax.
	+ Cons:
		- Requires jQuery to be loaded, which can increase page load times and add unnecessary dependencies.
		- May have performance issues if not optimized properly (e.g., using a loop instead of a recursive function).
* **Object.assign():**
	+ Pros:
		- Built-in method, so no additional library is required.
		- Fast and efficient, as it uses the `V8` JavaScript engine's built-in property merging algorithm.
	+ Cons:
		- May require more effort to use correctly, especially for those not familiar with its usage.

**Library and purpose:**

* `$.extend()`: a method provided by jQuery (a popular JavaScript library for DOM manipulation and event handling). Its primary purpose is to simplify the process of merging objects by providing a convenient way to merge multiple sources into an existing target object.
* `Object.assign()`: a built-in JavaScript method that was introduced in ECMAScript 2015. It's designed to provide a simple and efficient way to merge properties from one or more source objects into an existing target object.

**Special JS feature or syntax:**

None mentioned in the provided benchmark, but it's worth noting that `Object.assign()` uses a feature called "call" (in older browsers) or "es6" method call (in modern browsers) which allows for more flexible function calls. The "call" method is used by `Object.assign()` to merge properties from source objects into the target object.

**Other alternatives:**

If you need to merge objects in JavaScript, there are a few other alternatives:

* **Loose equal operator (`===`)**: You can use `obj1 === obj2` to check if two objects are equal. However, this method does not create a new merged object; it simply checks if the objects have the same value.
* **`for...in` loop**: You can use a `for...in` loop to iterate over an object's properties and merge them into another object using `obj2[prop] = obj1[prop];`.
* **ES6 spread operator (`{ ... }`)**: In modern JavaScript environments, you can use the spread operator `{ ... }` to create a new merged object from multiple source objects: `const mergedObj = { ...obj1, ...obj2 };`.

Keep in mind that these alternatives may have different performance characteristics and usage patterns compared to `$.extend()` and `Object.assign()`.

Related benchmarks:

$.extend() vs Object.assign() (version: 0)

Comparing performance of: $.extend() vs Object.assign()

Created: 6 years ago by: Guest

Jump to the latest result

$.extend()

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):