Benchmark: className vs. setAttribute vs. classList (fixed syntax error)

HTML Preparation code:

<div id="foo" class="lorem"></div>

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className += " bar"; }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.classList.add("bar"); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
className
classList

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is comparing three approaches to adding a class to an HTML element:

1. `className` property (adding a string to the existing class names)
2. `setAttribute` method (setting an attribute with a specific value, in this case, a class name)
3. `classList` API (adding a class using the `add` method)

**Options Compared**

The benchmark is comparing two options for each approach:

* `className`: Using the `+=` operator to concatenate a new class name to the existing classes.
* `setAttribute`: Setting an attribute with a specific value, in this case, a class name.

**Pros and Cons of Each Approach**

1. **className**:
	* Pros: Simple, widely supported, and efficient for small-scale additions.
	* Cons: Can lead to performance issues when dealing with large numbers of classes or complex class names (due to string concatenation overhead).
2. **setAttribute**:
	* Pros: More flexible and powerful than `className`, as it allows setting any attribute value, not just a class name.
	* Cons: Less intuitive and more verbose than using the `className` property, which can lead to performance issues due to attribute lookup and parsing overhead.

3. **classList**:
	* Pros: Modern, efficient, and well-supported in modern browsers (including Firefox 80). It also provides additional features like class list manipulation and event delegation.
	* Cons: Less widely supported than `className` or `setAttribute`, although it's getting more common with each passing year.

**Library Usage**

None of the benchmark test cases use a library, but they do rely on the following APIs:

* `document.getElementById`: Used to retrieve an HTML element by its ID.
* `Element.className` and `Element.classList`: The property and API used to manipulate class names.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax being tested in this benchmark. It's focused on comparing the performance of three simple approaches to adding classes to an HTML element.

**Other Alternatives**

If you're interested in exploring alternative approaches, consider these:

* Using a CSS-in-JS solution like Emotion, styled-components, or css-in-js (which might provide better optimization and flexibility).
* Utilizing a library like jQuery, which provides a more convenient and feature-rich API for working with classes and attributes.
* Implementing custom class management solutions using JavaScript, such as class-based inheritance or event-driven approaches.

Keep in mind that these alternatives might introduce additional overhead, dependencies, or complexity to your project. The benchmark's simplicity and focus on basic class manipulation make it an excellent starting point for exploring performance optimizations in this context.

Related benchmarks:

className vs. setAttribute vs. classList (fixed syntax error) (version: 0)

Comparing performance of: className vs classList

Created: 5 years ago by: Guest

Jump to the latest result

className

classList

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):