Benchmark: Dom benchmark - MeasureThat.net

HTML Preparation code:

<div id="i1">
  <div id="i2">
    <div id="i4" class="c1">
      <div class="c5">
        <div class="c4">

        </div>
        <div class="c5">

        </div>
      </div>
    </div>
    <div class="c7">
      <div class="c6">

      </div>
    </div>
    <div id="i3" class="c2">
      <div class="c3">
        <div class="c4">
          <div class="c8">
            <span>
				Find me
            </span>
          </div>
        </div>
        <div class="c5">

        </div>
      </div>
    </div>
  </div>
</div>

Tests:

one-liner found
var r = function () { return document.getElementById('i3').querySelector('span'); }()
if breakout found
var r = function () { var e = document.getElementById('i3'); return e ? e.querySelector('span') : null; }()
one-liner not found
var r = function () { return document.getElementById('i4').querySelector('span'); }()
if breakout not found
var r = function () { var e = document.getElementById('i4'); return e ? e.querySelector('span') : null; }()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
one-liner found
if breakout found
one-liner not found
if breakout not found

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is a complex task, and MeasureThat.net provides a valuable resource for benchmarking. To explain what's being tested on the provided JSON data, let's break down each test case.

**Benchmark Definition:**

The benchmark definition represents a single line of code or an entire function that's being executed repeatedly to measure its performance. In this case, there are four test cases:

1. **One-liner found**: The code `var r = function () { return document.getElementById('i3').querySelector('span'); }()` is being executed.
2. **If breakout found**: The code `var r = function () { var e = document.getElementById('i3'); return e ? e.querySelector('span') : null; }()` is being executed, which includes an "if breakout" (more on this later).
3. **One-liner not found**: Similar to the first test case, but the query selector is applied to a different element (`#i4`).
4. **If breakout not found**: Similar to the second test case, but the query selector is not used if the element is not found.

**Options compared:**

These four test cases compare two approaches:

* **One-liner vs. If breakout**: The first two test cases use a one-liner approach (querying `document.getElementById('i3').querySelector('span')`) and an "if breakout" approach (`var e = document.getElementById('i3'); return e ? e.querySelector('span') : null;`), which checks if the element exists before applying the query selector. The third and fourth test cases use a one-liner approach, but with different elements.
* **Element selection vs. Not found**: The first two test cases use an "if breakout" approach that checks for the existence of the element before applying the query selector. This is compared to using a one-liner approach without any checks (third and fourth test cases).

**Pros and Cons:**

1. **One-liner approaches**: These approaches are concise and may be faster since they don't involve an additional check for the element's existence.
2. **If breakout approach**: This approach can provide better performance if the element is not found, as it avoids unnecessary DOM queries.

However, there are also potential downsides:

* **One-liner approaches**: If the query selector fails, the function will return `null`, which may lead to unexpected behavior in some cases.
* **If breakout approach**: If the element is not found, this approach can result in an empty result or a slower execution time due to the additional check.

**Library and syntax:**

MeasureThat.net uses standard JavaScript libraries and syntax. The test cases rely on:

* `document.getElementById()` to retrieve elements by their IDs.
* `querySelector()` to select elements based on CSS selectors.
* `var` declarations for variable assignments.
* Function literals (e.g., `function () { ... }`) to define small functions.

**Other alternatives:**

If you want to explore alternative approaches, here are some ideas:

1. **Use a library like Lodash**: Lodash provides utility functions that can simplify DOM queries and element selection, such as `_.getElementByAttribute()` or `_.getElementBySelector()`.
2. **Experiment with different query selectors**: Try using other CSS selectors, such as attribute selectors (`[attr]`) or class selectors (`.[class]`), to see if they provide better performance.
3. **Consider using a more modern JavaScript approach**: For example, you could use `requestAnimationFrame()` to optimize the benchmarking process.

Keep in mind that these alternatives may require changes to your test code and might not be suitable for all use cases.

I hope this explanation helps you understand what's being tested on MeasureThat.net!

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36

Browser/OS: Chrome 56 on Mac OS X 10.12.3

View result in a separate tab

Test name	Executions per second
one-liner found	1673076.5 Ops/sec
if breakout found	1675214.4 Ops/sec
one-liner not found	1671844.2 Ops/sec
if breakout not found	1686949.1 Ops/sec

Related benchmarks:

Dom benchmark (version: 0)

Comparing performance of: one-liner found vs if breakout found vs one-liner not found vs if breakout not found

Created: 7 years ago by: Guest

Jump to the latest result

one-liner found

if breakout found

one-liner not found

if breakout not found

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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