Benchmark: JS / jQuery selector variables

HTML Preparation code:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>

Script Preparation code:

$body = $('body');
bodyEl = document.body;

var app = {};
app.getBody = function() {
  return $body;
}
app.getBody2 = function() {
  return $('body');
}

Tests:

#A
$body
#B
$('body')
#C
bodyEl
#D
document.body
#E
app.getBody
#F
app.getBody2

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
#A
#B
#C
#D
#E
#F

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/104.0.0.0 Safari/537.36

Browser/OS: Chrome 104 on Windows

View result in a separate tab

Test name	Executions per second
#A	10884934.0 Ops/sec
#B	1279581.2 Ops/sec
#C	10978406.0 Ops/sec
#D	5281403.0 Ops/sec
#E	19082512.0 Ops/sec
#F	19034860.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Context**

The benchmark is designed to test performance differences in JavaScript when using various approaches to access the `body` element of an HTML document. The tests are comparing different methods for retrieving or accessing the body element, including:

1. jQuery selector syntax (`$('body')`)
2. jQuery variable reference (`$body`)
3. Direct property access (`document.body`)
4. Method invocation on an object (`app.getBody()` and `app.getBody2()`)
5. Native JavaScript object property access (`bodyEl`)

**Library**

The benchmark uses the jQuery library, which is a popular JavaScript library for DOM manipulation and event handling. In this case, jQuery's `$(selector)` syntax is used to select elements from the document.

**Special JS Features or Syntax**

None of the test cases explicitly use any special JavaScript features or syntax beyond what's standard in modern JavaScript implementations. However, the benchmark does rely on the existence of a global `window` object and its associated properties (e.g., `document.body`) for accessing the DOM elements.

**Options Being Compared**

The benchmark compares the performance differences between various approaches to access the body element:

1. **jQuery selector syntax**: `$('body')`
2. **jQuery variable reference**: `$body`
3. **Direct property access**: `document.body`
4. **Method invocation on an object**: `app.getBody()` and `app.getBody2()`
5. **Native JavaScript object property access**: `bodyEl`

**Pros and Cons of Each Approach**

Here's a brief summary of the pros and cons for each approach:

1. **jQuery selector syntax**:
	* Pros: Convenient, easy to read, and flexible (can be used with various selectors).
	* Cons: May incur additional overhead due to the use of jQuery's DOM manipulation engine.
2. **jQuery variable reference**:
	* Pros: Similar to direct property access but leverages jQuery's caching mechanism.
	* Cons: Can be less readable than other approaches, especially for those unfamiliar with jQuery.
3. **Direct property access**: `document.body`
	* Pros: Fastest and most straightforward approach.
	* Cons: May not work in all environments (e.g., older browsers) or when the document is still loading.
4. **Method invocation on an object**:
	* Pros: Encourages encapsulation and separation of concerns.
	* Cons: May incur additional overhead due to method lookup and invocation.
5. **Native JavaScript object property access**: `bodyEl`
	* Pros: Fastest and most straightforward approach, similar to direct property access.
	* Cons: May not work in all environments (e.g., older browsers) or when the document is still loading.

**Other Considerations**

When choosing an approach, consider the following factors:

* Performance: Direct property access (`document.body`) is likely to be the fastest, followed by native JavaScript object property access (`bodyEl`). jQuery selector syntax and variable reference approaches may incur additional overhead.
* Readability: jQuery selector syntax can be more readable for those familiar with the library, while direct property access and native JavaScript object property access may require more expertise in DOM manipulation.
* Environment support: Direct property access and native JavaScript object property access may not work in all environments. jQuery selector syntax and variable reference approaches are likely to be more forgiving.

**Alternatives**

Other alternatives for accessing the body element could include:

1. Using the `document.documentElement` property instead of `document.body`.
2. Utilizing a library like `dom-traversal` or `select` for more complex DOM selection scenarios.
3. Implementing custom caching mechanisms to reduce the number of DOM accesses.

Keep in mind that these alternatives may come with additional trade-offs in terms of performance, readability, and compatibility.

Related benchmarks:

JS / jQuery selector variables (version: 5)

Comparing performance of: #A vs #B vs #C vs #D vs #E vs #F

Created: 8 years ago by: Registered User

Jump to the latest result

#A

#B

#C

#D

#E

#F

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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