Benchmark: querySelector vs querySelectorAll testsss

HTML Preparation code:

<li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li />

Tests:

querySelector
for(let i = 0; i < 5000; i++) document.querySelector('li:nth-child(5)')
all
for(let i = 0; i < 5000; i++) document.querySelectorAll('li')[5]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
all

Fastest: N/A

Slowest: N/A

Latest run results:

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

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**Benchmark Definition and Script Preparation Code**

The provided benchmark definition json represents a test case that compares the performance of two approaches: `querySelector` and `querySelectorAll`. The script preparation code is empty, which means that no specific JavaScript code needs to be executed before running the benchmark.

The HTML preparation code provides a simple list of 11 `<li>` elements, with the 5th element being the target element for both test cases. This setup allows the benchmark to focus on the performance difference between `querySelector` and `querySelectorAll`.

**Individual Test Cases**

There are two test cases:

1. **"querySelector"`**: This test case uses the `document.querySelector` method to select the 5th `<li>` element from the list using its index (`:nth-child(5)`). The loop iterates 5000 times, simulating a large number of executions.
2. **"all"`**: This test case uses the `document.querySelectorAll` method to select all `<li>` elements and then access the 5th element at index `[5]`. Again, the loop iterates 5000 times.

**Library and Purpose**

Both tests use the DOM (Document Object Model) API, which is a set of APIs that provide programmatic access to HTML documents. The `document.querySelector` and `document.querySelectorAll` methods are part of this API.

**Pros and Cons of Each Approach**

1. **"querySelector"`**:
	* Pros: More efficient and optimized for this specific use case, as it only searches for the target element without returning all matching elements.
	* Cons: May not be suitable for other scenarios where you need to select multiple elements or perform more complex queries.
2. **"all"`**:
	* Pros: More flexible and can be used in scenarios where you need to select multiple elements or perform more complex queries.
	* Cons: Less efficient than `querySelector` for this specific use case, as it returns all matching elements and then filters out the unwanted ones.

**Special JS Feature**

There is no special JavaScript feature or syntax being tested here. The benchmark focuses on the performance difference between these two simple DOM API methods.

**Other Alternatives**

If you need to select multiple elements from the same set, you can use other approaches:

* `document.querySelectorAll` with a CSS selector (e.g., `.class`): Returns all elements with the specified class.
* `Array.prototype.slice()` or `Array.prototype.splice()`: Slice or splice an array of matching elements.

However, these alternatives may not be as efficient as `querySelectorAll` in some cases, especially when dealing with large datasets.

Related benchmarks:

querySelector vs querySelectorAll testsss (version: 0)

Comparing performance of: querySelector vs all

Created: 2 years ago by: Guest

Jump to the latest result

querySelector

all

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):