Benchmark: querySelector vs querySelectorAll test

HTML Preparation code:

<content id="demo">Hello World!</content>

Script Preparation code:

let components = '';
for (let i=0; i<10000; i+=1) {
    components += '<div class="component" data-component="component' + i + '">Content ' + i + '</div>'
}
document.getElementById("demo").innerHTML = components;

Tests:

querySelectorAll
let components = document.querySelectorAll('[data-component]');
querySelector
let components = document.querySelector('[data-component]');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelectorAll
querySelector

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
querySelectorAll	7848.0 Ops/sec
querySelector	5971923.5 Ops/sec

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 and its options.

**Benchmark Overview**

The benchmark is designed to compare the performance of two JavaScript methods: `querySelector` and `querySelectorAll`. The test creates a large HTML string with 10,000 `<div>` elements, each containing unique data attributes. The goal is to find all or one specific element within this string using these two methods.

**Options Compared**

The benchmark compares the following options:

1. **`querySelector```**: This method returns the first matching element, specified by its CSS selector.
2. **`querySelectorAll```**: This method returns a NodeList containing all elements that match the specified CSS selector.

**Pros and Cons of Each Approach**

*   **`querySelector```**
    *   Pros:
        *   Less memory-intensive since it only retrieves one element at a time
        *   May be faster in cases where a single matching element is expected
    *   Cons:
        *   Returns `null` if no matching element is found, requiring additional checks
        *   Can lead to slower performance when dealing with large datasets
*   **`querySelectorAll```**
    *   Pros:
        *   Efficiently retrieves all matching elements in a single operation
        *   Reduces memory usage since only one request is made for multiple results
    *   Cons:
        *   Returns an empty NodeList if no elements match the selector
        *   May be slower due to increased computation and potential additional DOM queries

**Library Usage**

There are no libraries mentioned in the benchmark definition or test cases.

**Special JavaScript Features/Syntax**

There is one special feature used: `[data-component]`. This is a CSS selector syntax that uses attribute selectors. It's a modern way of selecting elements based on their attributes, rather than traditional class or ID selectors. The browser being tested (Chrome 120) likely supports this syntax.

**Other Alternatives**

If `querySelector` and `querySelectorAll` are not suitable for the benchmark, alternative approaches might include:

*   Using a library like Lodash, which provides a `querySelectorAll` function that returns a more efficient result set
*   Implementing your own custom selector engine using JavaScript
*   Utilizing web worker threads or other parallel computing techniques to speed up computations

Related benchmarks:

querySelector vs querySelectorAll test (version: 0)

Comparing performance of: querySelectorAll vs querySelector

Created: 2 years ago by: Registered User

Jump to the latest result

querySelectorAll

querySelector

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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