Benchmark: Object.assign vs spread operator for settting values

HTML Preparation code:

<script
  src="https://code.jquery.com/jquery-3.4.1.js"
  integrity="sha256-WpOohJOqMqqyKL9FccASB9O0KwACQJpFTUBLTYOVvVU="
  crossorigin="anonymous"></script>

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var other = Object.assign({ b:"world", c: false, d:2 }, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var other = { b:"world", c: false, d:2, ...params };
jQuery extend
var params = { b:"hello", c: true, d:7 }; var other = $.extend({ b:"world", c: false, d:2 }, params);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator
jQuery extend

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 dive into the explanation.

**Benchmark Overview**

The provided JSON represents a JavaScript benchmark test case created on MeasureThat.net. The test measures the performance difference between three approaches: `Object.assign`, the spread operator (`...`), and jQuery's `$.extend()`. The test is focused on setting values in an object, specifically comparing the execution time of these approaches.

**Benchmark Definition**

The benchmark definition specifies a JavaScript function that creates two objects, `params` and `other`. `params` has properties `b`, `c`, and `d` with initial values. The objective is to set the values of `other` to match those in `params`.

There are three test cases:

1. **Object.assign**: Uses the `Object.assign()` method to copy the properties from `params` to `other`.
2. **Spread Operator**: Uses the spread operator (`...`) to create a new object and merge the properties from `params` into it.
3. **jQuery extend**: Uses jQuery's `$.extend()` function to combine the properties of two objects.

**Options Compared**

The benchmark compares the performance of these three approaches:

*   **Object.assign**: A built-in JavaScript method for copying properties from one object to another.
*   **Spread Operator**: A new operator introduced in ECMAScript 2018, allowing for concise object creation and merging.
*   **jQuery extend**: A utility function provided by jQuery for combining objects.

**Pros and Cons of Each Approach**

1.  **Object.assign**: Pros:
    *   Widely supported across browsers and JavaScript environments.
    *   Fast and efficient execution time.
2    Cons:
    *   Less readable code due to the verb-noun format ("assign" object).
    *   Limited support for recursive property assignment.
3.  **Spread Operator**: Pros:
    *   Concise and expressive syntax, making it easy to read and write.
    *   Can handle recursive property assignments using nested spread operators (`{ ... }`).
4    Cons:
    *   Less widely supported across older browsers or JavaScript environments (pre-ES2018).
    *   May have slower execution times due to the additional syntax complexity.

5.  **jQuery extend**: Pros:
    *   Wide support for various object merging scenarios.
    *   Familiar and readable syntax for developers already familiar with jQuery.
6    Cons:
    *   Requires including the jQuery library, adding overhead in terms of size and loading time.
    *   Less efficient execution times compared to native `Object.assign()`.

**Library Usage**

The test case uses jQuery's `$.extend()` function as an alternative approach. This is done to demonstrate how this utility can be used for object merging, even though it has its own set of trade-offs (more on that below).

**Special JavaScript Feature/Syntax**

None are mentioned explicitly in the benchmark definition.

**Other Alternatives**

In addition to the three approaches tested, other methods for object merging exist:

*   **Object.create()**: Can be used to create a new object with a prototype.
*   **Array.prototype.reduce()**: Could potentially be used for more complex object merges.
*   **For loops and objects**: Manual iteration can also be employed for object merge operations.

**Conclusion**

In conclusion, the benchmark measures the performance of three approaches for setting values in an object: `Object.assign`, the spread operator (`...`), and jQuery's `$.extend()`. Each approach has its pros and cons regarding readability, browser support, execution time, and library usage. This test case helps developers understand the trade-offs involved in choosing these alternatives for specific use cases.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser/OS: Chrome 79 on Windows

View result in a separate tab

Test name	Executions per second
Object.assign	4240415.5 Ops/sec
spread operator	15960379.0 Ops/sec
jQuery extend	3699234.5 Ops/sec

Related benchmarks:

Object.assign vs spread operator for settting values (version: 0)

Comparing performance of: Object.assign vs spread operator vs jQuery extend

Created: 4 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

jQuery extend

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):