What's the best way to build localized RAG in user's browser?

Hey community, great to meet you all. This is AI Republic here, quick q, what's the bast way to build a localized vector database into user's browser. Any way we can use utilize indexDB to build RAG?

Background here: AI Republic is building a privacy preserving AI assistant that living in browser, AI Republic Helper. And we want to create a localized RAG db to store user's personal data to enable personalized AI search. We know indexDB currently is the best option, but haven't found too much info about using it as a vector DB or to build the RAG. What's the best practice? Anyone tried before?