Add the yarn mode

[ChappIO]

Note: I had to change NPM_BADGE_URL in the site to test this locally. Any particular reason for not using window.location to determine this value?

[LucaScorpion]

Nice addition, thanks! Just some console.log debug statements which can be removed, but other than that it seems nice.

As for the NPM_BADGE_URL variable, that's a good point. iirc the main reason I set it up like this is that I haven't set up a proxy in the frontend, so I can't just call /npm/.... But this is definitely not the best, I'll see if I can set up something nicer for that in future.

[ChappIO]

@LucaScorpion No proxy?

It worked fine for me. Eleventy builds into _site and express serves _site on port 3000. So http://localhost:3000 has both site and /npm

Also: Fixed the linting issues.

[LucaScorpion]

Uhh hm, you're right, I must have been thinking about another setup 😅 Sounds like it should be straightforward enough then, will look at that soon! For now, I'll merge this 🚀