Benchmark: JS: insertBefore vs append

HTML Preparation code:

<div id="container"></div>

Script Preparation code:

var container = document.getElementById("container");
var paragraphs = new Array( 100 ).fill( 'p' );

Tests:

insertBefore
paragraphs.forEach( p => container.insertBefore( document.createElement( p ), null ) );
append
container.append( ...paragraphs.map( p => document.createElement( p ) ) );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
insertBefore
append

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided JavaScript microbenchmark.

**What is being tested?**

The benchmark compares the performance of two approaches to insert HTML elements:

1. `insertBefore`: Inserting each paragraph element before an empty `null` node (i.e., no existing sibling).
2. `append`: Appending all paragraph elements as children of the container.

**Options compared:**

* `insertBefore` vs `append`
* Using `document.createElement()` to create new HTML elements
* Using the `forEach()` method to iterate over the array of paragraphs

**Pros and cons of each approach:**

* `insertBefore`:
	+ Pros:
		- May be faster because it doesn't require creating a new DOM element for each paragraph.
		- Can take advantage of the browser's existing DOM structure.
	+ Cons:
		- Requires creating an empty node (`null`) as the second argument, which can lead to issues if not handled correctly.
		- May not be compatible with all browsers or edge cases.
* `append`:
	+ Pros:
		- Simpler and more straightforward approach.
		- Does not require creating empty nodes or handling complex browser behavior.
	+ Cons:
		- May be slower due to the overhead of creating a new DOM element for each paragraph.

**Library usage:**

None of the provided benchmarks explicitly use any external libraries. However, some browsers may include internal APIs (e.g., `Array.prototype.forEach()`).

**Special JS feature or syntax:**

The benchmarks do not mention any special JavaScript features or syntax, such as async/await, Promises, or modern JavaScript language features.

**Other alternatives:**

If you wanted to add additional tests, you could consider comparing other approaches, such as:

* Using `DOMElement.insertAdjacentHTML()` instead of `createElement()`
* Inserting paragraphs in reverse order (i.e., last element first) to see if it affects performance
* Using a different container structure (e.g., `div` with multiple child elements)

Keep in mind that adding more tests would require modifying the benchmark definition and script preparation code.

**Benchmark preparation code:**

The provided script preparation code creates an array of 100 paragraph elements (`paragraphs`) filled with `'p'` content, and then defines a container element to insert or append the paragraphs. The HTML preparation code includes a basic `div` container with an ID of `"container"`.

Feel free to ask if you'd like me to clarify any part of this explanation!

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36 Edg/114.0.1823.67

Browser/OS: Chrome 114 on Windows

View result in a separate tab

Test name	Executions per second
insertBefore	10338.2 Ops/sec
append	10927.9 Ops/sec

Related benchmarks:

JS: insertBefore vs append (version: 0)

Comparing performance of: insertBefore vs append

Created: 2 years ago by: Guest

Jump to the latest result

insertBefore

append

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):