Possibly relevant reading you may have already seen

:)

http://redis.io/topics/indexes#representing-and-querying-graphs-using-an-hexastore
http://nodejsconfit.levelgraph.io/
http://crubier.net/Hexastore/
http://factis.io/

This issue contains links about Redis indexes, hexastores, and Node.js graph storage, but names no files, tests, or implementation entry point. Read the linked material to determine whether it supports a concrete graph-storage feature; the issue needs a defined scope and completion criteria before work can be considered done.

Written by the indexing model from the issue text.