My app does not use ember-data, it uses only apollo for graphql to retrieve/manage data.
But after installing emberfire, we must have to install ember-data too.
We just use emberfire/firebase for authentication :)
If I try to remove it I've got an error:
Cannot find module 'ember-data/package.json' from '/Users/bruno/octane-graphql/node_modules/emberfire'
The solution here is simple: don't use emberfire!
Basically the entire concept of emberfire is to intergrate firebase into ember-data. If you just want to use some firebase services use the firebase sdk directly.