I've been using stylua for a long time for my other non-playdate lua projects. It's a formatting tool completely separate from any editor you might use, and it's great for just enforcing a coding style and not having to manually format things.
However it couldn't handle <const> tags from Lua 5.4 that the Playdate uses until recently. I opted to not use those attribute so that I could still have stylua run on my playdate projects. The newer version does support it now though!