The benchmark defined on MeasureThat.net involves a comparison between two different methods of retrieving the maximum divisor of a number: one method uses sorting followed by reversing the sorted results, while the other method employs a direct sort of the results. Both methods iterate through the divisors of numbers generated in an array using the forEach method.

Benchmark Overview

1. Input Preparation:
   Both benchmark tests start by preparing an array of 10,000 random integers, each between 0 and 10,000. This setup provides uniform input for both test cases.

2. Test Cases:

   • Sort and Reverse Method:

     array.forEach(n => {
       const repeat = Math.sqrt(n);
       const result = [[], []];
     
       for (let i = 1; i <= repeat; i++) {
           if(n % i === 0) {
               result.push(i);
               if (i !== repeat) result.push(n / i);
           }
       }
     
       result.sort().reverse()[0];
     });
     

     This approach sorts the divisors of n, reverses the sorted array to retrieve the largest divisor, and accesses the first index.

   • Sort Method:

     array.forEach(n => {
       const repeat = Math.sqrt(n);
       const result = [[], []];
     
       for (let i = 1; i <= repeat; i++) {
           if(n % i === 0) {
               result.push(i);
               if (i !== repeat) result.push(n / i);
           }
       }
     
       result.sort()[result.length-1];
     });
     

     In this approach, the divisors are sorted, and the last element of the sorted array (which is the largest) is directly accessed.

Comparison of Approaches

• Pros of Sort and Reverse:

  • The operation is clear and aligns well with the concept of retrieving the maximum value.
  • It can be easier to read and understand for developers familiar with stack operations.

• Cons of Sort and Reverse:

  • It involves two separate operations: sorting and reversing, which may introduce more overhead compared to directly accessing the maximum element.
  • This can be less efficient in terms of performance, especially when handling a large array of divisors.

• Pros of Sort only:

  • It utilizes a single sort operation followed by direct access to the last element, which can be more efficient in terms of performance.
  • This approach minimizes the number of operations performed, which can have performance benefits.

• Cons of Sort only:

  • In cases where the implementation is less clear, it might take developers a moment to ensure that accessing the last element returns the maximum.

Benchmark Results

The benchmark results show that both methods executed approximately 30 times per second. The sorting followed by accessing the last element performed slightly better, with 30.30 executions per second compared to the sort-and-reverse method’s 30.09 executions per second.

Other Considerations and Alternatives

• Complexity: Both methods involve a time complexity of O(n log n) due to sorting. Alternative algorithms for finding the maximum divisor could potentially reduce this complexity (linear search or heap data structures), especially in specific circumstances.

• Alternative Libraries:
  While the benchmark does not utilize external libraries, tools like Lodash or Underscore can offer utility functions for dealing with arrays, including sorting and manipulating data efficiently. However, this might add overhead and complexity if not used properly.

• Special JavaScript Features:
  The benchmark uses ES6 features such as const and arrow functions, which enhance readability and maintainability of the code. The Array.from method generates a new array from the given iterable or array-like structure, which is a modern JavaScript feature that makes it easier to create arrays from other data types.

This benchmark provides a practical introduction to performance testing in JavaScript. Understanding the underlying algorithms and comparing them helps optimize performance for similar scenarios.