persp-projectile VS apheleia

I am currently trying with perspective rather than persp-mode, as it segregates the buffer list as I like (#1 above). I've got projectile with persp-projectile, and that seems to give me what I need for project navigation (#2 probably, still not 100%). I get some help in my mode line for project focus (#3, partially).

Aye. I often have two interdependent projects I work on simultaneously, and I use a lot of persp-projectile (https://github.com/bbatsov/persp-projectile). I would love to try project.el but sadly it seems like it doesn't integrate with perspective.el yet.

I also use purely emacs for "commercial programming" (as you refer to it) and for managing multiple projects I use projectile + perspective + persp-projectile.

I had my own rolled version of this in my config until recently when I swapped to perspective and perspective-projectile.

For black, I can recommend apheleia. It handles not only black but also all the other common formatters (not only for Python), with custom ones being relatively easy to add.

1.projectile-kill-buffers or the built-in project-kill-buffers will do that for the current project. You could run that before switching projects.

2. https://github.com/radian-software/apheleia

3. There might be a way to do this but I'm not sure. Emacs being inherently single threaded probably makes this difficult. But yes, I use M-x (re)compile.

4. libvterm is the best still imo. You can definitely do multiple instances and there's even different tab modes in Emacs now.

I forgot to mention a third option namely lassik/emacs-format-all-the-code and there are efforts to combine/consolidate the three into a single package which would be great.

raxid502/apheleia

I use formatters in order to automatically format source code on save. Personally I use apheleia for this. It requires clang-tools installed as it uses clang formatter.

Generally speaking, emacs does only so much for indenting those mixed mode files, so you might want to use a dedicated JS(X)-formatter (default one would be prettier). I can recommend integrating it using apheleia. It automatically prettifies buffers on save, but without having your cursor jump around like prettier-mode does. It also relies on having the prettier script available (from npm i -g prettier or its likes).