react-native-firebase-storage | Example using Firebase Storage and Camera | Authentication library

I am using the react native template from this article. The code is all available on Github here.

You can use the app to record audio and save to the file system. I figured out how to retrieve the file URIs, but I'm finding it impossible to get the actual contents of the file itself. All I want to do is retrieve the actual file contents as a binary or ascii or hex string or whatever (it's a .m4a file), so I can convert it to base64 encoding and then post it as JSON to my server. Here's what my code looks like:

/src/screens/RecordAudioScreen/RecordAudioScreenContainer.js