This benchmark titled "variadics vs arrays" tests the performance differences between two ways of passing parameters to functions in JavaScript: using variadic parameters (...args) versus passing an array. Specifically, it examines whether the variadic syntax is faster or slower than traditional array argument passing when handling a set of string inputs.

Options Compared

1. Variadic Parameters (...args):

   • Test Name: "variadic"
   • Benchmark Definition:

     function test(...args) {
         let finalRep = '';
         for (const item of args) {
             finalRep = item.toString();
         }
         return finalRep;
     }
     const frep = test('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z');
     

   • Mechanism: The function accepts any number of string arguments, stored in the args array-like structure. It converts each item to a string and keeps overwriting finalRep with the last string's value.

2. Array as Argument:

   • Test Name: "array"
   • Benchmark Definition:

     function test(args) {
         let finalRep = '';
         for (const item of args) {
             finalRep = item.toString();
         }
         return finalRep;
     }
     const frep = test(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']);
     

   • Mechanism: This function takes a single array argument. It iterates through the array, converting each item to a string and overwriting finalRep similarly to the variadic version.

Performance Results

The benchmark results show that:

• The function using the array approach executed at 11,909,563 executions per second.
• The function using variadic parameters executed at 10,713,618 executions per second.

Pros and Cons

Variadic Parameters

• Pros:

  • More flexible, as you can pass a varying number of arguments without needing to wrap them in an array.
  • Can improve the readability of calls in certain scenarios.

• Cons:

  • Can incur a slightly higher overhead due to the creation of an array-like structure to hold arguments for each function call, which may result in slower performance.

Array as Argument

• Pros:

  • The approach can be more efficient for performance-sensitive applications, as it requires less overhead during argument preparation.
  • Easier to work with when you need to pass a predefined collection of items since they're already grouped in an array.

• Cons:

  • Requires you to create and potentially manage an array, which could be less intuitive when dealing with a dynamic number of arguments.

Other Considerations

• The choice between these two methods doesn't just rest on performance; it also relates to code readability and maintainability depending on the specific use case at hand.
• For any performance-sensitive code, it's crucial to consider the potential overhead associated with the chosen method.

Alternatives

• Object Arguments: Instead of using variadic parameters or arrays, an object can be used to encapsulate related data items. This approach can enhance clarity when many parameters are involved, though it may add some overhead in terms of object creation.
• Rest Parameters in Combination with Arrays: You can use a combination of array spread syntax (...array) and object destructuring to create even more flexible APIs.

These benchmarks help inform developers not only about performance but also guide them in choosing the right structure based on their specific use case.