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

Benchmark Overview

The benchmark is designed to compare two approaches for retrieving all elements on a web page:

1. querySelectorAll('*'): This method uses the querySelectorAll() function, which returns a NodeList containing all elements that match the specified selector.
2. TreeWalker (document.createTreeWalker()): This approach uses a TreeWalker to traverse the DOM tree and collect all elements.

What's being tested?

The benchmark is testing the performance of these two approaches on different browsers (Chrome 99) and devices (Desktop).

Options compared

The benchmark is comparing:

• querySelectorAll('*'): The first option uses querySelectorAll() with a wildcard selector ('*') to get all elements.
• TreeWalker (document.createTreeWalker()): The second option uses TreeWalker to traverse the DOM tree and collect all elements.

Pros and Cons of each approach

querySelectorAll('*'):

Pros:

• Fast and efficient
• Wide browser support

Cons:

• May return duplicate elements if there are multiple elements with the same selector
• Can be less flexible than other selectors, such as querySelector() or querySelectorAll()

TreeWalker (document.createTreeWalker()) :

Pros:

• More flexible than querySelectorAll(), allowing for more specific selectors
• Can return unique elements

Cons:

• May be slower due to the overhead of traversing the DOM tree
• Requires more code and setup compared to querySelectorAll()

Library used

In this benchmark, no specific library is mentioned. However, in general, TreeWalker is a built-in browser API for navigating the DOM tree.

Special JS features or syntax

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

Other considerations

• Browser support: The benchmark only includes Chrome 99 and may not be representative of other browsers.
• Device platform: The benchmark is only tested on Desktop devices, which may affect performance.
• DOM structure: The benchmark's DOM structure is designed to contain multiple article elements with similar selectors, which can impact the performance comparison.

Alternatives

Other alternatives for retrieving all elements on a web page include:

• Using document.body.querySelectorAll() with a more specific selector, such as document.body.querySelectorAll('.class')
• Using a library like jQuery or vanilla JavaScript libraries (e.g., $(), $.each()) to simplify the process
• Using a different traversal approach, such as using Array.from() and element.matches()