Hi Loc,

After speaking with Andres, the author of this article, he explained that yes, Quill is still usable in 2019. In fact, if you go to their Github repository you can see that they are often working on the project and that it is well maintained. Some other options worth checking out are ProseMirror, Summernote or Draftjs to see if any of those suit your requirements more.

I hope that helps! Good luck!