Work with elm.json and docs.json

This package is meant for people creating Elm tooling, like editor plugins. If you just want to make stuff in Elm, there is nothing here for you.

Both package.elm-lang.org and elm reactor needed the functionality provided by this package, and over time, it became clear that this subset can be reasonably shared.

Finding Metadata Files

Elm creates a per-user cache of package information. This cache is READ-ONLY. Do not modify or add files to it. Inside the cache, you have the elm.json and docs.json for every package that has been downloaded and built. This means you can just read them locally and do whatever sort of visualization or analysis you want.

Note: The per-user cache of package information lives at the directory specified in the ELM_HOME environment variable. If this environment variable is not set, it defaults to ~/.elm/ on UNIX systems and C:/Users/<user>/AppData/Roaming/elm on Windows. Again, do not modify or add files in ELM_HOME for your work because:

1. It will be very confusing and frustrating if this cache is corrupted.
2. This cache is cleared very infrequently, so it should be as small as possible.

If you need to cache information for your plugin, it is better to find a separate solution. Use the local elm-stuff/ directory so that it is easy for users to (1) delete if there is a problem and (2) reclaim the storage.