surveyRoute.js

app.post("/api/survey/webhooks", bodyParser.urlencoded(), (req, res) => {
  const p = new Path("/api/survey/:surveyId/:choice");
  const { recipient: email, url, event } = req.body;
  const match = p.test(new URL(url).pathname);
  if (match && event === "clicked") {
    Survey.updateOne(
      {
        _id: match.surveyId,
        recipients: {
          $elemMatch: { email: email, responded: false }
        }
      },
      {
        $inc: { [match.choice]: 1 },
        $set: { "recipients.$.responded": true },
        lastResponded: new Date()
      }
    ).exec();
  }

  res.send({});
});