Benchmark: children vs queryselector

HTML Preparation code:

<div><custom-element></custom-element></div>

Tests:

children
const divs = document.querySelectorAll("div") Array.from(divs).map(div => { div.children[0] })
queryselector
const divs = document.querySelectorAll("div") Array.from(divs).map(div => { div.querySelector('custom-element') })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
children
queryselector

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 16 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:149.0) Gecko/20100101 Firefox/149.0

Browser/OS: Firefox 149 on Linux

View result in a separate tab

Test name	Executions per second
children	1179913.4 Ops/sec
queryselector	1099138.2 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 MeasureThat.net and explore what's being tested in this benchmark.

**Benchmark Definition**

The benchmark is designed to compare two approaches: `children` and `querySelector`. The test case uses HTML with a custom element (`<custom-element>`) inside a `<div>` container. This setup allows us to focus on the differences between accessing elements using the `children` property versus the `querySelector` method.

**Options Compared**

The benchmark compares two options:

1. **Accessing elements using `children`:**
	* `const divs = document.querySelectorAll("div")`
	* `Array.from(divs).map(div => { div.children[0] })`
2. **Accessing elements using `querySelector`:**
	* `const divs = document.querySelectorAll("div")`
	* `Array.from(divs).map(div => { div.querySelector('custom-element') })`

**Pros and Cons of Each Approach**

1. **Children approach:**
	* Pros:
		+ Can be faster, since it only requires a single DOM traversal.
		+ May be more efficient for accessing elements that are direct children of the queried element.
	* Cons:
		+ Less flexible, as it's limited to direct children.
		+ May not work if the accessed element is not a direct child (e.g., due to event listeners or other DOM modifications).
2. **QuerySelector approach:**
	* Pros:
		+ More flexible, as it can access elements using any CSS selector.
		+ Works even if the accessed element is not a direct child.
	* Cons:
		+ May be slower due to additional DOM traversals.

**Library and Purpose**

In this benchmark, no specific library is used. However, `document.querySelectorAll()` and `Array.from()` are built-in JavaScript methods for querying the DOM.

**Special JS Feature or Syntax (None)**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Other Alternatives**

If you're interested in exploring other alternatives, here are a few:

1. **CSSOM**: You could use CSS selectors to query elements and then access their children using `children`.
2. **XPath**: Another option would be to use XPath expressions to select elements and then access their children.
3. **Custom implementation**: Depending on your specific requirements, you might want to implement a custom method for accessing child elements.

Keep in mind that these alternatives may have different performance characteristics compared to the original approaches being tested in this benchmark.

Related benchmarks:

children vs queryselector (version: 0)

Comparing performance of: children vs queryselector

Created: 4 years ago by: Guest

Jump to the latest result

children

queryselector

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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