Is there a practical use case for this system? It looks great. I want to parse out textual data and this system seems to only work on numbers sets.
It will be interesting to see how this scientific JS toolchain evolves. Would be fun to get a more feature-complete Propel ML working with Mike Bostock's Observable project:
Seems to be quite far away. IIRC, there are a lot of immature, scattered math libs for JS.
Most of the ML libs I've seen are proof-of-concept, like brain.js or synapse. Those libs seem to implement basic perceptrons and other textbook examples, but not much else.