net is covered already by https://www.npmjs.com/package/react-native-tcp.
fs is covered by https://www.npmjs.com/package/react-native-level-fs which in turn is covered by mafintosh's fs on leveldb, and leveldb itself is in RN's AsyncStorage. In the end, all goes to AsyncStorage which is just a cross-platform abstraction for "storage, but expect things to work asynchronously". http://facebook.github.io/react-native/releases/0.42/docs/asyncstorage.html It's backed by RocksDB, if available.