Not exactly answering your question, but I‘ve found researching CRDTs (Conflict-free Replicated Data-Types) very enlightening. It‘s what a lot of databases use

Not exactly answering your question, but I‘ve found researching CRDTs (Conflict-free Replicated Data-Types) very enlightening. It‘s what a lot of databases use these days for multi-master replication. Martin Kleppmann has done some great writing about its P2P use-cases. As for your actual question: GunJS comes to mind and looks interesting but I‘m not sure it‘s production ready.