Request for feature to filter primitive values with either OR or NOT #1924

I'm attempting to build a MongoDB-to-Datastore proxy. It must be stateless and Dockerized, so that I can scale it easily vertically. To do this, I've decided to base my work off https://github.com/Cordazar/crest

I faced 2 challenges:

• Lack of support for a Not-Equal filter - I have decided to make do by proxying it for two inequalities (A != B is equivalent to A < B OR A > B)
• Lack of support for a Not-In filter - I have decided to use an inequalities approach again since it seems to apply it against all individual elements

The one I'm unable to plan for is the lack of support for OR queries. Will my proxy have no way of expressing these in NodeJS? When is functionality for this planned for release with the Node lib? (I was unable to find any open discussions on the same on the GitHub issues)

I can make multiple queries but this will make the internal workings of my proxy rather complex, and I'd really be happy to avoid it if possible. Mathematically speaking, the only option is a standard De-morgan transform, ie. using AND(NE(A), NE(B)) = OR(A, B). This is impossible to implement if at the primitive level, we don't have both OR, as well as NOT.

Lastly, am I trying to reinvent the wheel and is it possible that something similar to what I'm attempting to build is already available?

Thanks,
Angad