Oh man, I'm using whitequarks smollTcp crate on my device. It's very nice!
But now I needed to configure device IP's on the server from the browser. So I need to parse the IP's the user enters.
So I looked for a nice looking library and found ipaddr.js
Looking it up on github shows it's also made by whitequark!

Her code is now present from the lowest to the highest point in my stack 😜