Benchmark: var vs document.body

HTML Preparation code:

<div class="test"></div>

Tests:

var
var db = document.body; db.querySelectorAll(".test")
document.body
var db = document.body; document.body.querySelectorAll(".test")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
var
document.body

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'll explain the test case described in the provided JSON.

**What is tested?**

The benchmark measures the performance difference between two approaches to access the `body` element of an HTML document using JavaScript.

In the first test case, `"var db = document.body; db.querySelectorAll('.test')"`, a variable `db` is declared and assigned the value of `document.body`. Then, the `querySelectorAll()` method is called on the `db` variable to retrieve all elements with the class `test`.

In the second test case, `"var db = document.body; document.body.querySelectorAll('.test')"`, another variable `db` is declared and assigned the value of `document.body`. However, instead of assigning the result of `document.body` to `db`, the `querySelectorAll()` method is called directly on the `document.body` object.

**Options compared**

The two approaches being compared are:

1. Assigning the result of `document.body` to a variable (`var db = document.body;`)
2. Calling `querySelectorAll()` directly on the `document.body` object without assigning it to a variable (`document.body.querySelectorAll('.test')`)

**Pros and Cons of each approach**

1. **Assigning to a variable:**
	* Pros:
		+ Can be useful for caching the result or reusing it in subsequent operations.
		+ Might improve performance if the `querySelectorAll()` method is called multiple times with the same selector.
	* Cons:
		+ Requires an additional assignment operation, which can introduce overhead.
		+ May not be necessary in this specific case, as `querySelectorAll()` is only called once.
2. **Calling directly on the object:**
	* Pros:
		+ Eliminates the need for an extra assignment operation, reducing overhead.
		+ Can be more concise and easier to read.
	* Cons:
		+ May not improve performance in this specific case, as `querySelectorAll()` is only called once.

**Library and purpose**

There is no explicit library mentioned in the provided JSON. However, `querySelectorAll()` is a method of the `Element` interface in JavaScript, which is part of the DOM (Document Object Model) API. The DOM API provides an interface for manipulating and querying HTML documents.

**Special JS feature or syntax**

There are no special JavaScript features or syntax mentioned in the provided JSON.

Related benchmarks:

var vs document.body (version: 0)

Comparing performance of: var vs document.body

Created: 8 years ago by: Guest

Jump to the latest result

var

document.body

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):