I think you have not understood what RxDB is.
It is a client side database. It works also when the client is offline. It does not need a stable internet connection over a websocket.
Your example is similar to RethinkDB and others. A websocket streaming json.
A more common solution includes using Datascript[1] as the client side DB and then using something like Posh[2] or Datsync[3] to handle query/pull subscription changes.
Your example is similar to RethinkDB and others. A websocket streaming json.