from here

my_color_contrast.js

var textColor = function (bgColor) {
  var output = runNetwork(bgColor);
  if (output.black > .5) {
    return 'black';
  }
  return 'white';
}

var runNetwork = function anonymous(inputs) {
  var net = {"layers":[{"r":{},"g":{},"b":{}},{"0":{"bias":10.762609321045387,"weights":{"r":-1.6101593793420965,"g":-8.079421879958582,"b":-7.882746791637501}},"1":{"bias":7.175588252506214,"weights":{"r":-1.0511422879361831,"g":-5.602044992104212,"b":-6.278794890237195}},"2":{"bias":18.851966380700553,"weights":{"r":-7.484336046810216,"g":-15.237355119365034,"b":-3.489557046149576}}},{"black":{"bias":12.649899021596282,"weights":{"0":-10.474642369487578,"1":-7.487009391808981,"2":-19.021313930174223}}}]};

  for(var i = 1; i < net.layers.length; i++) {
    var layer = net.layers[i];
    var outputs = {};
    for(var id in layer) {
      var node = layer[id];
      var sum = node.bias;
      for(var iid in node.weights)
        sum += node.weights[iid] * inputs[iid];
      outputs[id] = (1/(1 + Math.exp(-sum)));
    }
    inputs = outputs;
  }
  return outputs;
}