If you want a live version of most of the site (including tracking new comments in items you've already looked at), I made this to improve my React skills when the HN API first came out:
I just wish there was a dark mode.. Let me install night reader to see how well it looks :p
Edit: would've loved if there was a way to sign up or make comments from there, oh well :< I wish there was, I am not sure if that's possible tho but I hope it could be.
https://insin.github.io/react-hn