I don't know why but this line doesn't work var sizes = _([inputSize, hiddenSizes, outputSize]).flatten();

[bitplanets]

this

 var sizes = _([inputSize, hiddenSizes, outputSize]).flatten();

returns a lodash wrapper instance instead of an array. Please do this instead:

var sizes = _.flatten([inputSize, hiddenSizes, outputSize]);

If not your lib is not usable with lodash

brain/lib/neuralnetwork.js

Line 99 in 6b58dc2

var sizes = _([inputSize, hiddenSizes, outputSize]).flatten();

also at line 527.