Benchmark: DOM structure: bottom up vs top down

Tests:

Bottom up
const ul = document.createElement('ul'); for (const d of '123456') { const li = document.createElement('li'); li.textContent = d; ul.appendChild(li); } const container = document.createElement('div'); container.appendChild(ul);
Top down
const ul = document.createElement('div') .appendChild(document.createElement('ul')); for (const d of '123456') { const li = document.createElement('li'); li.textContent = d; ul.appendChild(li); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Bottom up
Top down

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser/OS: Firefox 132 on Linux

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Test name	Executions per second
Bottom up	132957.1 Ops/sec
Top down	141914.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided benchmark.

**Benchmark Definition**

The benchmark definition is quite simple, yet it highlights two different approaches to creating an unordered list (`ul`) and its child elements (`li`).

1. **Bottom-up approach**: This method starts by creating an empty `ul` element using `document.createElement('ul')`. Then, a loop iterates over the string '123456' to create each `li` element inside the `ul`. Finally, all `li` elements are appended to the `ul` using `appendChild`.
2. **Top-down approach**: This method starts by creating an empty `div` element and then appending a newly created `ul` element directly to it using `.appendChild(document.createElement('ul'))`. Then, another loop creates each `li` element inside the `ul` in the same way as before.

**Comparison of options**

The two approaches differ in their DOM tree creation:

* **Bottom-up approach**: The DOM tree is built from scratch with each node created individually.
* **Top-down approach**: A pre-existing `div` element serves as a container, and its child `ul` element is appended to it directly.

**Pros and Cons**

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

**Bottom-up approach**

Pros:

* Easier to understand and maintain
* More explicit control over DOM tree structure

Cons:

* May incur additional overhead due to repeated DOM creation
* Less efficient if the same elements need to be created multiple times

**Top-down approach**

Pros:

* Can lead to better performance by reusing existing nodes in the DOM tree
* Simplifies certain types of rendering or layout calculations

Cons:

* Can make the code more complex and harder to understand
* Adds an additional step to manage the pre-existing `div` container

**Library usage**

In this benchmark, no libraries are explicitly mentioned. However, if we consider modern JavaScript frameworks or libraries that manipulate the DOM, some might argue that a virtual DOM library like React or Preact could provide optimized implementations of these approaches.

**Special JS features or syntax**

None are mentioned in this specific benchmark definition.

Related benchmarks:

DOM structure: bottom up vs top down (version: 0)

Comparing performance of: Bottom up vs Top down

Created: 3 years ago by: Guest

Jump to the latest result

Bottom up

Top down

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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