Let's break down the benchmark and its results.

What is being tested?

The benchmark is testing three different ways to concatenate (add) arrays in JavaScript:

1. Array.prototype.concat(): The traditional method of concatenating arrays using the concat() function.
2. Spread operator (...): The new ES6 spread operator, introduced in 2015, which allows you to expand an array into its elements.
3. push() with spread syntax ([ ...params ] inside push()): A more recent approach that uses the spread operator inside the push() function.

Options compared

The benchmark is comparing these three approaches for concatenating arrays. The options are:

• Traditional concat()
• Spread operator (...)
• push() with spread syntax

Pros and Cons of each approach

1. Traditional concat():
   • Pros: Well-established, widely supported, and easy to understand.
   • Cons: Can be slower than newer approaches and may lead to array duplication when using concat() in a loop.
2. Spread operator (...):
   • Pros: More efficient and concise than traditional concat(), reducing the chance of array duplication.
   • Cons: Requires ECMAScript 2015 or later support, which might not be available on older browsers or environments.
3. push() with spread syntax:
   • Pros: Similar to the spread operator but allows for more flexibility in assigning values to individual elements after concatenation.
   • Cons: Requires a newer JavaScript engine that supports push() with spread syntax.

Library and special JS features

There are no libraries or special JavaScript features used in this benchmark, except for:

• The spread operator (...), which is a new feature introduced in ECMAScript 2015.

Other alternatives

If you want to consider other approaches, here are some additional options that were not tested in this benchmark:

• Array.prototype.push.apply(): A function call-based approach to concatenating arrays.
• Array.prototype.reduce() and reduceRight(): Array methods used for reducing an array into a single value, which can be used with concatenation.

Keep in mind that these alternatives might have different performance characteristics or use cases compared to the approaches tested in this benchmark.