Let's break down the benchmark and explain what's being tested.

What is being tested?

The benchmark is comparing two approaches for formatting numbers in JavaScript:

1. Intl.NumberFormat: This approach uses the Internationalization API to format numbers according to a specific locale (in this case, English-US).
2. toLocalString: This approach uses the toLocaleString method of the Number object to format numbers.

Options being compared:

The two approaches are being compared in terms of their performance, specifically the number of executions per second.

Pros and cons of each approach:

1. Intl.NumberFormat:
   • Pros:
     • Provides more control over formatting options (e.g., decimal separator, thousand separator).
     • Can handle complex number formats.
   • Cons:
     • May be slower due to the additional overhead of creating an Internationalization object.
2. toLocalString:
   • Pros:
     • Typically faster than Intl.NumberFormat, as it uses a built-in method.
   • Cons:
     • Less control over formatting options.
     • May not handle complex number formats correctly.

Library and purpose:

The Intl library is part of the JavaScript standard library. It provides functionality for working with internationalization and localization, including date and time formatting, number formatting, and more.

In this benchmark, the Intl.NumberFormat approach uses the NumberFormat class to format numbers according to a specific locale (in this case, English-US).

Special JS feature or syntax:

This benchmark does not use any special JavaScript features or syntax that are not commonly used in everyday development. It's focused on comparing two simple and well-supported approaches for formatting numbers.

Other alternatives:

If you're looking for alternative ways to format numbers in JavaScript, you could consider using other libraries like Moment.js or date-fns, which offer more advanced formatting options. However, keep in mind that these libraries may add additional overhead and dependencies to your project.

For simple use cases, the toLocalString approach is often sufficient and faster than using Intl.NumberFormat.

Overall, this benchmark provides a good starting point for understanding the performance differences between two commonly used approaches for formatting numbers in JavaScript.