Javascript’s regular expression library is becoming world class, guaranteeing that the odd little pattern language will likely be around for generations to come.

So I'm working with Cypress and I'm attempting to understand how to verify a URL via regex matching; but I want to use several character sets in the regex, and I want to add a variable as well ...

That’s what [Low Level JavaScript] points out about regular expressions. Sure, a lot of people think they are scary. So why not write your own regular expression parser and engine?

The latest JavaScript specification standardizes a well-balanced and thoughtful set of features, including the built-in global Iterator, new Set methods, improvements to regular expressions, and more.