Repo from Svelte Society Day presentation.
The example Sapper project uses rollup-plugin-replace for environment variable replacement. Any environment variable prefixed with SOCIETY_ will automatically be replaced in the code if it's listed as a process.env.* variable. For example:
process.env.SOCIETY_JWT_SECRET
Is replaced with with the JWT secret.
process.env.NODE_ENV is the only non-prefixed variables replaced.