Benchmark: firstElementChild vs children[0]

HTML Preparation code:

<html>

<body>
    <div id='test'>
        <div name='a'></div>
        <div name='b'></div>
        <div name='c'></div>
    </div>
</body>

</html>

Script Preparation code:

var parent = document.getElementById('test');

Tests:

firstElementChild
const b = parent.firstElementChild
children[0]
const a = parent.children[0]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
firstElementChild
children[0]

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what is being tested.

**Benchmark Definition**

The benchmark is comparing two ways to list children of an HTML element:

1. `parent.firstElementChild`
2. `parent.children[0]`

This means we're trying to determine which method is faster for a given scenario.

**Options Compared**

The two options are being compared in terms of their performance, with the aim of finding the fastest way to list children. The options themselves are quite simple:

* `parent.firstElementChild`: This method returns the first element among the child nodes of the parent element.
* `parent.children[0]`: This method returns the first child node of the parent element.

**Pros and Cons**

Both methods have their pros and cons:

* `parent.firstElementChild`:
	+ Pros: This method can be more efficient when dealing with only one or a few children, as it avoids iterating over all child nodes.
	+ Cons: If there are many children, this method may still require iteration, which could lead to slower performance compared to `children[0]`.
* `parent.children[0]`:
	+ Pros: This method always returns the first child node, regardless of how many children there are. It avoids iteration altogether.
	+ Cons: If there is only one child, this method will still iterate over all other children to find it.

**Other Considerations**

When writing JavaScript code that needs to traverse a DOM tree, you need to consider factors like:

* The size of the tree (number of nodes)
* The type of node (element or text node)
* The browser and its engine version

**Library/Functionality Used**

In this benchmark, there is no specific library being used. However, the `document.getElementById` function is being used to get a reference to an HTML element (`parent`). This is a built-in JavaScript API.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark.

**Other Alternatives**

If you're looking for alternatives to compare child nodes, some other methods could be:

* Using `Array.prototype.forEach` or `for...in` loop to iterate over all child nodes
* Using a library like jQuery (although this might not be the case here)
* Using a more modern approach with HTML collections (available in ECMAScript 2015 and later)

In summary, this benchmark is comparing two simple methods for listing children of an HTML element: `parent.firstElementChild` and `parent.children[0]`. The pros and cons of each method have been discussed, as well as other considerations when working with DOM trees.

Related benchmarks:

firstElementChild vs children[0] (version: 0)

Fastest way to list children

Comparing performance of: firstElementChild vs children[0]

Created: 3 years ago by: Guest

Jump to the latest result

firstElementChild

children[0]

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):