Writes an attribute at the user level indicating the direction the NPS score is going. This way you can easily find all users who are decreasing in nps rating

post_nps.js

//Returns the category of the customer based on the NPS score,
const getCategory = nps => {
  if (nps > 8) return "promoter";
  if (nps > 6) return "passive";
  return "detractor";
}

if (changes && changes.user) {
  const { nps_rating } = changes.user;
  // If the NPS Rating Changes
  if (nps_rating[0]!==undefined) {
    hull.traits({
      // Tells you if the latest score was an increase or a drecrease.
      direction: nps_rating[1] > nps_rating[0] ? "increase" : "decrease"
      category: getCategory(nps_rating[1])
    }, { source: "nps" });
  }
}