Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

Benchmark Overview

The benchmark measures the performance difference between four different ways to add a class to an HTML element:

1. jQuery addClass method
2. jQuery classList.add method (with $() notation)
3. querySelector with classList.add
4. getElementById with classList.add

Comparison

The benchmark compares the performance of these four approaches in Chrome 78 on a Windows 7 desktop.

Here's a brief overview of each approach:

• jQuery addClass method: This is a simple method that adds a class to an element without removing any existing classes. It's widely used in web development but can lead to issues if not used carefully.
• jQuery classList.add method (with $() notation): This method uses the classList property of the element and adds a new class to it. The $() notation is used to select the element, which can be slower than using querySelector.
• querySelector with classList.add: This approach uses the querySelector API to select an element by its CSS selector and then calls classList.add on that element.
• getElementById with classList.add: This approach uses the getElementById method to retrieve an element by its ID and then calls classList.add on that element.

Pros/Cons of each approach

Here's a brief summary:

• jQuery addClass method:
  • Pros: Simple, widely supported
  • Cons: Can lead to issues with class duplication, slower performance compared to other methods
• jQuery classList.add method (with $() notation):
  • Pros: More flexible than addClass, faster performance
  • Cons: Requires jQuery library, can be slower due to the extra step of selecting the element
• querySelector with classList.add:
  • Pros: Fast, efficient, modern API
  • Cons: Not supported in older browsers, may require additional setup for performance
• getElementById with classList.add:
  • Pros: Simple, fast
  • Cons: Requires retrieval of the element by its ID, which can be slower than using other methods

Library usage

The benchmark uses jQuery library to provide the addClass and classList.add methods. The querySelector method is a native API in modern browsers.

Special JS features/syntax

None of the test cases use special JavaScript features or syntax beyond what's standard for modern web development (e.g., no async/await, no let/catch).