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

What is being tested?

The main goal of this benchmark is to compare two approaches for adding a value to an array in JavaScript: using the push() method and using indexing (i.e., accessing an element at a specific index).

Options compared:

There are two options being compared:

1. Push: Using the push() method, which adds one or more elements to the end of the array.
2. Index: Using indexing to access an element in the array and assigning a new value.

Pros and Cons of each approach:

• Push:
  • Pros:
    • Easy to use and understand.
    • Modifies the original array.
  • Cons:
    • Can be less efficient for large arrays since it involves shifting elements when inserting at the end.
• Index:
  • Pros:
    • More flexible, as you can access any element in the array.
    • May be more efficient for small to medium-sized arrays since it avoids the overhead of shifting elements.
  • Cons:
    • Requires manual indexing, which can lead to errors if not done correctly.

Library:

There doesn't appear to be a specific library being used in this benchmark. However, some libraries like Lodash or Ramda provide utility functions for array operations, including push() and indexing.

Special JS feature/syntax:

This benchmark does not use any special JavaScript features or syntax that are not widely supported. The focus is on comparing the performance of two fundamental array operations in JavaScript.

Other alternatives:

In addition to these two approaches, other methods for adding a value to an array include:

• Using concat() and spreading the new element (aNumbers.concat(5))
• Using setInterval or another timing-based approach
• Using a different data structure, such as a linked list or a tree

However, these alternatives are not being compared in this benchmark.

Benchmark preparation code:

The provided script preparation code creates an array aNumbers with initial values and calculates its length. The index of the last element is stored in the variable aNumbersLenght.

In the HTML preparation code, no additional code is required since this is a JavaScript-only benchmark.

Let me know if you have any further questions or need clarification on any aspect of the benchmark!