Benchmark: Inspecting the dom

HTML Preparation code:

<div id="rhs">
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
    <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
    <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
    <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
    <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
  <div>
    <div>
      <div>
        <a href="https://www.google.com/">Hello world</a>
      </div>
    </div>
  </div>
</div>

Tests:

Just push it
let elements = document.querySelectorAll("#rhs > div > div > div > a"); let s = []; for (let element of elements) { s.push(element.href); }
Regexp
let elements = document.getElementsByTagName("a"); let s = []; let regex = new RegExp(/https:\/\/www\.google\.com/); for (let element of elements) { if (regex.test(element.href)) { s.push(element.href); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Just push it
Regexp

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 24 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark is designed to test how fast different approaches are to extract URLs from HTML elements. The main variation between the two test cases is:

1. **`document.querySelectorAll`**: This method returns a NodeList of all elements that match the specified CSS selector (`#rhs > div > div > div > a`). In contrast, `document.getElementsByTagName` returns an HTMLCollection (an older API).
2. **Regular expression usage**: The first test case uses a simple `for...of` loop to iterate over the NodeList and push the URLs into an array. The second test case uses a regular expression (`/https:\\/\\/www\\.google\\.com/`) to filter the elements before pushing their URLs into an array.

**Comparison of options**

1. **`document.querySelectorAll`**: This method is generally faster than `document.getElementsByTagName` because it's more efficient and doesn't require creating a separate HTMLCollection.
2. **Regular expression usage**: The first test case uses a simple loop to iterate over the NodeList, while the second test case uses regular expressions to filter elements. Regular expressions can be slower due to their computational complexity.

**Pros and Cons**

1. **`document.querySelectorAll`**:
	* Pros: Faster, more modern API.
	* Cons: Requires Modern JavaScript features (e.g., `const`, `let`, arrow functions).
2. **Regular expression usage**:
	* Pros: More flexible and powerful for complex filtering tasks.
	* Cons: Can be slower due to regular expression overhead.

**Other considerations**

1. **Browser support**: Both methods are supported by modern browsers, but older versions may not have the same level of performance or feature support.
2. **CSS selector performance**: The CSS selector used in `document.querySelectorAll` can significantly impact performance. In this case, the selector is quite specific (`#rhs > div > div > div > a`), which might reduce the number of elements matched.

**Library usage**

None of the test cases explicitly use any external libraries beyond built-in JavaScript APIs.

**Special JS features or syntax**

1. **Arrow functions**: The `for...of` loop in both test cases uses arrow functions, which are available in modern JavaScript environments.
2. **Regular expressions**: Regular expression usage is a standard feature of JavaScript, but its performance can vary depending on the browser and engine used.

**Alternatives**

Other methods to extract URLs from HTML elements might include:

1. **`String.prototype.match()`:** This method returns an array of matches for a regular expression in a string.
2. **`HTMLParser`:** An API for parsing HTML documents, which can provide more control over the parsing process.

Keep in mind that these alternatives might have different performance characteristics or require additional setup compared to `document.querySelectorAll`.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/118.0

Browser/OS: Firefox 118 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Just push it	69847.8 Ops/sec
Regexp	40976.5 Ops/sec

Related benchmarks:

Inspecting the dom (version: 0)

Comparing performance of: Just push it vs Regexp

Created: one year ago by: Guest

Jump to the latest result

Just push it

Regexp

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 24 days ago):