Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

Overview

The benchmark compares three approaches for creating an array from a string:

1. Array.from(): a built-in method that creates an array from an iterable object, such as a string.
2. String Split: manually splitting the string into an array using the split() method with an empty string ('') as the separator.
3. Spread Operator (also known as the rest operator): creating a new array by spreading elements of an existing array (in this case, a single-element array containing the original string).

Options Comparison

Let's analyze each approach and their pros and cons:

• Array.from():
  • Pros: efficient, concise, and widely supported.
  • Cons: might incur some overhead due to method call and iteration.
• String Split: manual splitting using split().
  • Pros: easy to implement, no dependencies on other libraries or methods.
  • Cons: slower and less readable compared to Array.from().

Library Usage

In this benchmark, the Array.from() method is a built-in JavaScript function. It doesn't rely on any external libraries.

Special JS Features/Syntax

The benchmark uses two special features:

1. Rest Operator (...): used in the spread operator approach to create a new array by spreading elements of an existing array.
2. Spread Operator Usage in Array Creation: using the rest operator to create a single-element array containing the original string, which is then passed to Array.from().

Other Alternatives

If you need to create an array from a string without using any built-in methods or libraries, you can consider the following alternatives:

1. Using map() and concat(): creating an array by mapping each character in the string to itself and concatenating the results.
2. Manually looping through each character in the string using a for loop and adding elements to an array.

Here's a simple example of the first alternative:

let n1 = [];
for (let i = 0; i < s1.length; i++) {
    n1.push(s1[i]);
}

And here's an example of the second alternative:

let n1 = [];
for (let i = 0; i < s1.length; i++) {
    for (let j = 0; j <= i; j++) { // Include the string itself as an element
        n1.push(s1[j]);
    }
}

Keep in mind that these alternatives are generally less efficient and more verbose than using Array.from() or the spread operator.