MongoDB Stitch webhook for IoT blog

webhook.js

exports = function(payload,response) {
  
  const mongodb = context.services.get("mongodb-atlas");
  const sensordata = mongodb.db("iotdb").collection("sensordata");
  
  var body = {};
  if (payload.body) {
    
    try{
      
    const document = EJSON.parse(payload.body.text());
    //sample document:{ "device" : "TempSensor1", "sample_date" : "2018-09-03", "value" : "72.5", "time" : "1536011844" }
    var sample={val:Number(document.value), time: Number(document.time) };
    var day=new Date(document.sample_date);
    
    sensordata.updateOne({"device":document.device,nsamples:{$lt:200},day:day},
                 {"$push":{samples:sample},
                  "$min":{first:sample.time},
                  "$max":{last:sample.time},
                  "$inc":{nsamples:Number(1)}},
                  {upsert:true}
              
                 ).then(result => {
    response.setStatusCode(201);
  });
    }
    catch(err) {
      console.log(err);
      response.setStatusCode(500);
    }
  
  }

};