You can try Prepack online here.
In addition to computing over concrete values, Prepack’s interpreter has the ability to operate on abstract values which typically arise from environment interactions.
Some libs had to be tweaked in order to work with Prepack. For example, y++; is not supported on abstract numbers but y = y + 1; works just fine.
Well, some libs are really good written and their initialization phase is quite simple and fast already. On top of that, Prepack adds type checking when working with abstract values, which may increase total lines of code and logic involved.
It’s always good to test new tools and find out if it suits your use case, like in Bluebird or RxJS case where it helped to speed up initialization time.
The short term goals for Prepack are more integration with React Native toolchain where we will see any improvements the most soon. After that, we can expect Prepack team to work on the web and node.js environments. There is still a long road ahead. If you would like to help feel free to do so on the GitHub repository.