Just one thing to consider here. The original maintainer is no longer supporting the Jasonette project. There is a parallel project called Jasonelle (github.com/jasonelle/jasonette-ios) where they forked the project and planned to do new developments. But that is also kind of not very active. So it might come down to owning a fork and implement the remaining feature yourself and then of course contribute back to community
git clone https://github.com/joshfire/jsonform.git?