Let's dive into explaining the JavaScript microbenchmark on MeasureThat.net.

Benchmark Definition

The benchmark is defined by providing a script preparation code and an HTML preparation code (which is empty in this case). The script preparation code defines an array of fruit names with some numbers embedded, representing the test data. The HTML preparation code is not used in this benchmark.

Test Cases

There are three individual test cases:

1. Push to new array: This test creates a new empty array firstFruits and then pushes every third element from the original fruits array into it.
2. Splice: This test removes two elements starting from the index i+1 from the original fruits array.
3. Filter: This test filters the original fruits array to only include elements whose index is a multiple of 3.

Options Compared

The three test cases compare different approaches for manipulating arrays:

• Using push() with creating a new array (Push to new array)
• Using splice() without modifying the original array (Splice)
• Using filter() with filtering out elements based on their index (Filter)

Pros and Cons of Each Approach

1. Push to new array

   • Pros: Easy to understand, efficient in terms of performance since it doesn't modify the original array.
   • Cons: Creates a new array, which can lead to memory allocation issues if not managed correctly.

2. Splice

   • Pros: Modifies the original array without creating a new one, thus potentially more memory-efficient compared to push().
   • Cons: More complex and less intuitive than using push() or filter(), may have performance issues if not used carefully.

3. Filter

   • Pros: Does not modify the original array, easy to read and maintain.
   • Cons: May be slower than splice() since it involves creating a new filtered array, which can lead to more memory allocation.

Libraries Used

None are explicitly mentioned in this benchmark. However, JavaScript's built-in methods like Array.prototype.push(), Array.prototype.splice(), and Array.prototype.filter() are used.

Special JS Feature or Syntax

The use of the arrow function (function(_, i) { return (i % 3 == 0); }) is a special feature. It provides a concise way to define small anonymous functions without declaring them as full-fledged functions using the function keyword.

Alternatives

If you were to rewrite these benchmarks, consider the following alternatives:

• Instead of creating a new array on each push operation (push()), consider using slice() or other methods to extract elements from the original array.
• When removing elements with splice(), consider handling edge cases like when the start index is out of range or when there are not enough elements left in the array.
• For filtering, consider using more efficient algorithms like map() or every() instead of filter() if performance is critical.

Keep in mind that these alternatives would depend on your specific requirements and constraints. The original approach provides a straightforward way to demonstrate each method's behavior.