// This does custom data preprocessing for the flight data.
// Modified from Crossfilter example code: https://github.com/square/crossfilter/blob/gh-pages/index.html#L231
function FlightsPreprocessor() {
  var my = new ChiasmComponent();

  my.when("dataIn", function (dataIn){
    my.dataOut = dataIn.map(function (d){
      d.date = parseDate(d.date);
      d.hour = d.date.getHours() + d.date.getMinutes() / 60;
      d.delay = Math.max(-60, Math.min(149, d.delay));
      d.distance = Math.min(1999, d.distance);
      return d;
    });
  });

  function parseDate(d) {
    return new Date(2001,
        d.substring(0, 2) - 1,
        d.substring(2, 4),
        d.substring(4, 6),
        d.substring(6, 8));
  }

  return my;
}