Remove unused exports / support of monorepo with frontend/backend code sharing

[Bessonov]

Hello snowpacker,

we use a monorepo with pnpm and webpack, and we want switch to snowpack. There are some things which stop us. One of them is that unused exports are not removed. We have helpers with frontend/backend abstraction. At the core like following repro https://github.com/Bessonov/snowpack-remove-unused :

• utils.js provides a set of helper functions.
• In index.js only frontend function is used.
• backend-function and the fs-import should be removed.

Is there any way to achieve that?