Feature Request: Auto Reformat on Execute & Save

[munro]

Hello!

I would love if

• my cell was automatically formatted on save
• automatically format all cells on save (hopefully this isn't slow, but I guess a dirty flag could be set?)

I'm using VS Code. When I'm working on .py files, VS Code automatically does black formatting (and import sorting!) when I save. I wish I had that in my notebooks in VS Code as well. 🥲

If I have time I may dig into how I add that.

[munro]

Oooo, it looks like it may be really easy, here's how autoreload extension is doing it:

https://stackoverflow.com/questions/32418123/run-code-before-an-ipython-notebook-cell-runs/73722066#73722066

And the pre save hook pre_save_hook!

https://jupyter-notebook.readthedocs.io/en/stable/extending/savehooks.html

[garrettargenna]

I would love this feature!