Benchmark: queryall vs classname

HTML Preparation code:

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

Tests:

queryAll
let start = performance.now(); let res = document.querySelectorAll('.test'); console.log(start - performance.now());
classname
let start = performance.now(); let res = document.getElementsByClassName('.test'); console.log(start - performance.now());

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
queryAll
classname

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
queryAll	170392.3 Ops/sec
classname	192812.8 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?**

The provided JSON represents two individual test cases: `queryAll` and `classname`. These tests aim to measure the performance difference between using `document.querySelectorAll()` (CSS selector) versus `document.getElementsByClassName()`, which takes a string argument representing the class name.

**Options compared:**

1. **CSS selectors (queryAll)**:
	* Pros:
		+ Easier to read and maintain, as it uses a CSS-like syntax.
		+ More flexible, allowing for more complex selections.
		+ Can be used with various pseudo-classes and attributes.
	* Cons:
		+ May have slower performance due to the complexity of parsing CSS selectors.
		+ Can be more resource-intensive, especially for large documents or complex selections.
2. **Class names (classname)**:
	* Pros:
		+ Typically faster and more lightweight than CSS selector-based methods.
		+ Easier to implement and maintain, as it only requires a simple string comparison.
	* Cons:
		+ Less flexible and less readable than CSS selectors.
		+ Not as suitable for complex selections or pseudo-classes.

**Library usage:**

There is no explicit library mentioned in the provided JSON. However, if we assume that `document.querySelectorAll()` and `document.getElementsByClassName()` are part of the DOM API (which they are), we can consider them as built-in JavaScript features.

**Special JS feature or syntax:**

The tests use a simple expression to measure performance, which is common in benchmarking scripts. The `performance.now()` function returns the current time in milliseconds, allowing us to calculate the execution time of the code.

Now, let's summarize the pros and cons of each approach:

* CSS selectors (queryAll):
	+ Pros: flexible, easy to read and maintain.
	+ Cons: may be slower, more resource-intensive.
* Class names (classname):
	+ Pros: faster, easier to implement and maintain.
	+ Cons: less flexible, less readable.

**Other alternatives:**

If you need to benchmark other approaches or JavaScript features, here are some alternatives:

1. **Regular expressions**: Instead of CSS selectors, you can use regular expressions to match elements in the DOM.
2. **Template literals**: You can use template literals (e.g., `template literals` instead of string concatenation) to improve code readability and performance.
3. **Async/await**: If you're interested in benchmarking asynchronous code, you can use async/await syntax.

Remember that the choice of approach depends on your specific requirements and the nature of your project.

Related benchmarks:

queryall vs classname (version: 0)

Comparing performance of: queryAll vs classname

Created: 2 years ago by: Guest

Jump to the latest result

queryAll

classname

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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