[nl]

It appears to be a custom NN implementation[1] in Javascript, somewhat similar to convnet.js[2]

As far as I can see the API[3] isn't much like TensorFlow.

[1] https://github.com/tensorflow/playground

[2] http://cs.stanford.edu/people/karpathy/convnetjs/

[3] https://github.com/tensorflow/playground/blob/master/nn.ts