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

What is being tested?

The benchmark tests two different approaches to find and remove an item from an array in JavaScript:

1. Array.filter(): This method creates a new array with all elements that pass the test implemented by the provided function.
2. Array.splice() + Array.indexOf(): This approach uses the indexOf() method to find the index of the element to be removed, and then uses splice() to remove the element at that index.

Options compared

The two options being compared are:

• Array.filter()
• Array.splice() + Array.indexOf()

Pros and Cons of each approach:

• Array.filter():
  • Pros:
    • More concise and expressive code
    • Creates a new array, which can be more memory-efficient for large datasets
  • Cons:
    • Can be slower than splice() + indexOf() for very large arrays (due to the overhead of creating a new array)
• Array.splice() + Array.indexOf():
  • Pros:
    • Faster execution time for large arrays (since it only modifies the original array)
  • Cons:
    • Less concise and expressive code
    • Can be more memory-intensive since it modifies the original array

Library used

The Array.filter() method is a built-in JavaScript method, introduced in ECMAScript 5.

Special JS feature or syntax

None are mentioned in this benchmark.

Other alternatives

There are other methods to remove an item from an array in JavaScript, such as:

• Using the map() method with the callback function returning an empty value (e.g., arr.map(item => item === 1E5 ? undefined : item)), but this is less efficient than using filter().
• Using a regular loop to iterate over the array and remove items (e.g., for (var i = 0; i < arr.length; i++) { if (arr[i] === 1E5) arr.splice(i, 1); }), but this is less concise than using filter() or splice() + indexOf().

The benchmark uses the most common and efficient approach for each method, which is why we see Array.filter() and Array.splice() + Array.indexOf() being compared.