Simple, embedded database deserve more attention, especially those with native language support, e.g. map,filter,reduce methods on wrapped data that behave simi

Simple, embedded database deserve more attention, especially those with native language support, e.g. map,filter,reduce methods on wrapped data that behave similar to javascript array; and support to nested data structure (like auto join and normalize). (I made one using Proxy API, called ref-db. The cons is it require manual indexing to speed up lookup by non-primary key)