I created parseUri v1 17 years ago, but never hosted it on GitHub/npm because it's older than both of those tools. Nevertheless, it’s been used very widely due to it being tiny and predating JavaScript’s built-in `URL` constructor. After this short gap, I just released v2 with a ton of improvements: https://github.com/slevithan/parseuri
It’s still tiny (nothing similar comes close, even with libraries that support far fewer URI parts, types, and edge cases), and it includes several advantages over JavaScript's built-in `URL` constructor:
* parseUri gives you many additional properties (authority, userinfo, subdomain, domain, tld, resource, directory, filename, suffix) that aren’t available from `URL`.
* `URL` throws e.g. if not given a protocol, and in many other cases of valid (but not supported) and invalid URIs. parseUri makes a best case effort even with partial or invalid URIs and is extremely good with edge cases.
* `URL`’s rules don’t allow correctly handling many non-web protocols. For example, `URL` doesn’t throw on any of 'git://localhost:1234', 'ssh://myid@192.168.1.101', or 't2ab:///path/entry', but it also doesn’t get their details correct since it treats everything after : up to ? or # as part of the pathname.
* parseUri includes a “friendly” parsing mode (in addition to its default mode) that handles human-friendly URLs like 'example.com/index.html' as expected.
* parseUri includes partial/extensible support for second-level domains like in '//example.co.uk'.
So although it’s needed less often these days because of the built-in `URL`, if `URL` is ever not enough for your needs, this is an extremely accurate, flexible, and lightweight option.
These days people study regular languages as part of the Chomsky hierarchy, but back when regular expressions were introduced into computing the term referred to Kleene’s regular expressions.
