Let's dive into the benchmark test case provided.

What is being tested?

This test case compares the performance of five different methods for creating a new array by copying the elements from another array (children). The methods being compared are:

1. Array.prototype.slice.call(children)
2. [ ...children ] (spread operator)
3. []; Array.prototype.push.apply(other, children) (push apply into empty array)
4. Array.from(children)
5. Object.values(children)

What options are compared?

The test case compares the execution time of these five methods for creating a new array by copying the elements from another array (children). The execution time is measured in executions per second.

Pros and Cons:

1. Array.prototype.slice.call(children)
   • Pros:
     • Supported by older browsers (before ES6)
     • Can be used to copy any type of collection (not just arrays)
   • Cons:
     • Slow compared to modern methods
     • Requires calling call() method on slice() function
2. [ ...children ] (spread operator)
   • Pros:
     • Fast and efficient
     • Supported by modern browsers (ES6+)
     • Simple and easy to read code
   • Cons:
     • Not supported in older browsers (before ES6)
3. []; Array.prototype.push.apply(other, children)
   • Pros:
     • Fast and efficient (similar to spread operator)
     • Supported by modern browsers (ES5+)
   • Cons:
     • Requires creating an empty array first
4. Array.from(children)
   • Pros:
     • Fast and efficient
     • Supported by modern browsers (ES6+)
     • Simple and easy to read code
   • Cons:
     • Not supported in older browsers (before ES6)
5. Object.values(children)
   • Pros:
     • Not applicable here, as it returns an array of property values, not a new array containing all elements.

Other considerations:

• The test case uses the children variable, which is assumed to be an HTMLCollection or NodeList obtained from document.body.children.
• The test results are specific to Chrome 66 on Mac OS X 10.13.4.
• The test case does not consider other factors that may affect performance, such as browser cache, JavaScript engine optimization, or CPU architecture.

Library and special JS feature:

• No external libraries are used in this test case.
• The spread operator ([ ...children ]) is a special JavaScript feature introduced in ES6 (2015).

Alternatives:

• Other methods for creating a new array by copying elements from another array include Array.prototype.concat() and using a loop to push each element into the new array. However, these methods are not compared in this specific test case.

I hope this explanation helps!