Where should I place a file of constants, to be accessed by app *AND* app extension?

[den232]

I have a file of constants (in javascript) which I need to access by both my app (/pages, /pages/components) AND my app extension (/appExtension/assets and /appExtension/blocks).

Where in the CLI-built directory structure can I place this file of common constants so both can access it, without duplicating the file (which would be problematic, right)?

Thanks!  jb