Re: Need assistance in figuring out what reformats my code on save

[Steinar Bang]

>>>>> Tassilo Horn <tsdh@gnu.org>:

> I'd try evaluating

>   (add-hook 'before-change-functions #'debug nil t)

> in a buffer where that formatting before save happens and then save.
> That should put you in the debugger and the backtrace will hopefully
> show you who and from where the formatting is triggered.

Thanks! That worked!

I did
 `M-: (add-hook 'before-change-functions #'debug nil t) RET`
in a .tsx buffer in a restarted emacs with nil before-save-hook and I
found that the reformatting is done by web-mode-on-post-command and is
run immediately after my change, and not just before save.

web-mode-on-post-command is run from the post-command-hook, and runs
indent-region on the buffer when the command is a yank
https://github.com/fxbois/web-mode/blob/master/web-mode.el#L2918

The formatting done by tide-format-before-save is different from the
formatting done by indent-region in web-mode-on-post-command, and with
tide-format-before-save in place, it's the tide-format-before-save
formatting that wins.

(In case someone finds this when googling: making tsfmt, or making
web-mode, format exactly like prettier, both seemed like too much work.
So I removed tide formatting from web-mode and used "prettier-js for
emacs" instead. See 
https://github.com/ananthakumaran/tide/discussions/434#discussioncomment-1285992
for details)