Benchmark: Static class query

HTML Preparation code:

<div class="test"></div>

Tests:

One
const one = document.querySelectorAll(".test");
Two
const two = Array.from(document.getElementsByClassName("test"));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
One
Two

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark.

**What is being tested?**

MeasureThat.net is testing the performance of two different methods to query elements with a CSS class using JavaScript:

1. `document.querySelectorAll(".test")`
2. `Array.from(document.getElementsByClassName("test"))`

These two methods are used to retrieve an array of DOM elements that match a specific CSS class.

**Options compared:**

The benchmark compares the performance of these two methods on different browsers and devices.

**Pros and Cons of each approach:**

1. **`document.querySelectorAll(".test")`:**
	* Pros:
		+ More modern and widely supported (it's been part of the DOM specification since 2004).
		+ Returns a `NodeList`, which is an array-like object that provides more flexibility than `Array.from`.
		+ Can be used to query elements with multiple CSS classes.
	* Cons:
		+ Has historically been slower than `Array.from` due to its more complex parsing process.
2. **`Array.from(document.getElementsByClassName("test"))`:**
	* Pros:
		+ Historically faster and more efficient than `document.querySelectorAll`.
		+ Uses the `getElementsByClassName()` method, which is optimized for performance on mobile devices.
	* Cons:
		+ Less modern and less widely supported (it's been deprecated in some browsers).
		+ Returns an HTMLCollection, which is not as flexible as a `NodeList`.

**Library/Technology used:**

The benchmark uses the JavaScript DOM API to interact with the document. Specifically, it uses:

* `document.querySelectorAll()` to query elements by class name
* `Array.from()` to convert an HTMLCollection to an array-like object
* `document.getElementsByClassName()` to retrieve elements by CSS class name

**Special JS feature/syntax:**

There is no special JavaScript feature or syntax used in this benchmark. However, the use of modern APIs like `document.querySelectorAll()` and `Array.from()` assumes a certain level of familiarity with modern JavaScript.

**Other alternatives:**

If you wanted to query elements with a CSS class using JavaScript, other alternatives could include:

* Using an CSS preprocessor like Sass or Less to generate the class names dynamically.
* Utilizing a library like jQuery to simplify DOM manipulation and event handling.
* Leveraging a framework like React or Angular to manage state and events.

In general, the choice of method depends on your specific use case, performance requirements, and personal preference.

Related benchmarks:

Static class query (version: 0)

Comparing performance of: One vs Two

Created: 5 years ago by: Guest

Jump to the latest result

One

Two

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):