Any rollup options to keep unused functions/variables in the bundle? | Vite Land | Page 1

First, it's my question about debugging on stackoverflow: https://stackoverflow.com/questions/75694857/rollup-how-to-preserve-keep-unused-variables
Second, I'd like to try to use Component::setupState and pick some "expected by a child component" functions defined in the parent component.
Unfortunately Rollup just purges them, I think such rude purging should be controllable.

OOPS. On the other hand, maybe Vue SFC compiler does that?
<script setup> is compiled and the setup state is returned from setup()
So the question is what module purges my unused functions/vars from <script setup>?

Stack Overflow

Rollup: how to preserve (keep) unused variables?

I'm using a Vite build rather than a dev version (server + HMR) on a traditional multi page site for developing. With --watch --minify false it's quite good.
The problem I need unused variables pre...

#Any rollup options to keep unused functions/variables in the bundle?