Let's dive into the world of JavaScript microbenchmarks!

Benchmark Definition and Purpose

The benchmark aims to compare the performance of three different approaches to manipulate an array of length 100,000:

1. slice: Creates a new array by copying a subset of elements from the original array.
2. splice: Mutates the original array by removing or inserting elements at specific positions.
3. shift: Removes and returns the first element of the array.

The benchmark measures which approach is the fastest to maintain a constant size of the array, while still performing the specified operation.

Options Compared

• slice vs splice vs shift
• Both splice and shift mutate the original array, whereas slice creates a new copy.
• splice can be slower due to its potential impact on the array's internal structure.
• shift can be faster since it only removes the first element, which is typically less expensive than modifying an array's middle or end elements.

Pros and Cons

• slice: Creates a new copy of the array, ensuring data integrity and avoiding side effects. However, this approach can be slower due to the overhead of creating a new object.
• splice: Mutates the original array, which may lead to unintended consequences if not used carefully. On the other hand, splice is typically faster than slice, especially for larger arrays, since it only requires modifying the existing data structure.
• shift: Removes and returns the first element of the array, making it a fast and efficient choice for certain use cases. However, it may not be suitable when the array is large or empty.

Library: Array.prototype.slice()

The slice() method creates a new array by copying a subset of elements from the original array. It takes two arguments:

• The start index (inclusive)
• The end index (exclusive)

In this benchmark, slice is used to create a copy of the first 99,999 elements of the array (list.slice(1)).

Library: Array.prototype.splice()

The splice() method modifies the original array by removing or inserting elements at specific positions. It takes two arguments:

• The index of the element to be removed (or inserted)
• The number of elements to remove (or insert)

In this benchmark, splice is used to remove the first element from the array (clone.splice(0, 1)).

Library: Array.prototype.shift()

The shift() method removes and returns the first element of the array. It does not modify the original array.

In this benchmark, shift is used to remove and return the first element of the array (list.shift()).

Special JS Feature/ Syntax

None mentioned in this benchmark.

Alternatives

Other approaches to manipulate arrays could be considered, such as:

• Using Array.prototype.map(), Array.prototype.filter(), or Array.prototypeforEach() instead of slice or splice.
• Using Array.prototype.concat() or Array.prototype.push() to add elements to the array.
• Implementing custom iteration logic using loops and indexing.

However, these alternatives may not be as efficient or effective as the original approaches used in this benchmark.