Check out this post here from the author of deeplearning.js

https://news.ycombinator.com/item?id=15856647

The big announcment:

We wanted to do hardware accelerated deep learning on the web, but we realized there was no NumPy equivalence. Our linear algebra layer has now matured to a place where we can start building a more functional automatic differentiation layer. We're going to completely remove the Graph in favor of a much simpler API by end of January.

Once that happens, we'll continue to build higher level abstractions that folks are familiar with: layers, networks, etc.

We really started from nothing, but we're getting there :)