Massively agree. Code mirror 5 was excellent. Code mirror 6 was a big enough improvement to justify the upgrade. I've used it as part of 2 large projects and it's handled every expanding use case I've needed it to. It supports themes, sql,js and 2 weeks ago I used its diff functionality. Really great library I can fully recommend.
Code mirror 6 is super hard to use though unless you are a front end expert. Code mirror 5 was basically plug and play. Code mirror 6 is a box of Legos and you are responsible to build and bundle your own editor from scratch.
I publish to npm because 1) Package managers are a fabulous idea. They're an easy way to download a package and it's dependencies, and update them over time. 2) it's not a good idea to push build artifacts to your repo, 3) This depends on CodeMirror, which is published to npm. Otherwise I would have to provide it too. That's too much work. 4) you don't need to be a Node developer to use npm.
> Code mirror 6 is a box of Legos and you are responsible to build and bundle your own editor from scratch.
Yep. Let me stress that there's absolutely nothing wrong with this if that's what you want to do -- but it's less than optimal for the person who just wants to add a JavaScript file for the editor, with maybe a JS/CSS combo to support syntax highlighting for a specific language. Codemirror 5 was like that, pretty much.
You basically have to set up a whole independent build and packaging system to configure Codemirror 6, and a lot of people just don't want to deal with that.
It's a pity it's the only JavaScript-based editor that works at all reliably on mobile (I would be delighted to be proven wrong about this).