In datomic/datascript, all data is stored in indexes and nowhere else. Therefore, yes, any query is using an index.

http://tonsky.me/blog/datascript-internals/ is a good read, as is http://tonsky.me/blog/unofficial-guide-to-datomic-internals/

@tonsky I'm just curious how you combine Rum with Datascript (given that you're the author of both libraries)

any patterns come up after some time using them?

do you feel the need of keeping queries inside React components (the way Om.next is doing)?

maybe you have more insights since "The web after tmr"