The provided benchmark evaluates different methods to retrieve the last element of a JavaScript array. Three distinct test cases are implemented, each using a different approach, allowing for a direct comparison of their performance. Here is a breakdown of each method, its pros and cons, and alternative strategies.

Test Cases:

1. Slice and Index

   • Code: var result = array.slice(-1)[0];
   • Method Explained: This approach utilizes the slice method to create a new array containing the last element of the original array and then accesses that element using indexing.
   • Pros:
     • Clear and straightforward syntax, beneficial for readability.
     • Works with negative indices which can be useful in more complex scenarios.
   • Cons:
     • Creates a new array, thereby incurring additional memory overhead.
     • Potentially slower due to the extra step of creating a new array.

2. Spread and Pop

   • Code: var result = [...array].pop();
   • Method Explained: This approach uses the spread operator (...) to create a shallow copy of the original array and then employs the pop method to remove and return the last element of the copied array.
   • Pros:
     • The spread operator can be quite versatile, making this method applicable in various situations where array copying is needed.
   • Cons:
     • Similar to the first method, it creates a new array in memory, leading to increased memory usage and performance costs.
     • The pop method modifies the array, which, combined with spreading, can lead to confusion about the original array's integrity.

3. Get by Length

   • Code: var result = array[array.length - 1];
   • Method Explained: This straightforward approach retrieves the last element directly by calculating the index using the array's length property.
   • Pros:
     • Most efficient in terms of both speed and memory usage, as it does not create any additional arrays.
     • Very clear and easy to understand for anyone familiar with JavaScript.
   • Cons:
     • Lacks the flexibility that methods utilizing slicing or spreading offer.

Benchmark Results Analysis

From the benchmark results, we see the following performance outcomes:

• Get by Length approach had the highest executions per second at 251,725,984, indicating that it is the most efficient method for this operation.
• Spread and Pop performed moderately with 68,780,424 executions per second, and was followed closely by Slice and Index with 68,380,208 executions per second. Both of these approaches are dramatically slower due to their memory allocation overhead.

Other Considerations and Alternatives

• Memory Usage: The slice and spread methods' creation of new arrays can lead to performance degradation, especially with larger arrays. In scenarios where performance is critical—such as in real-time data processing or when processing large arrays—avoiding unnecessary memory allocation is essential.
• Alternatives:
  • array.at(-1) is another option available in modern JavaScript, which allows for retrieving the last element directly with negative indexing without creating a new array. This might provide a balance of readability and performance.
  • For performance-sensitive applications, consider using typed arrays (e.g., Uint8Array, Float32Array) which provide better performance for numerical computations.

In conclusion, while there are various methods to retrieve the last element of an array in JavaScript, the simplest and most efficient technique is to use the array's length as an index. This comparison highlights the trade-offs between code readability and performance, which is a common consideration in software engineering.