Parametrium
Parametrium ↗ is a parameter space explorer for P5.js sketches.
It allows users to interactively move through parameter space of all the code constants, without modifying anything in code.
You can find more details (including info on AST transformations) in this blog post: building parametrium.
Live version is running on github pages: http://szymonkaliski.github.io/parametrium ↗, and code is open sourced: szymonkaliski/parametrium ↗.