How to load 2 different Firestore docs in one 'onUpdate' Cloud Function?

Question

I am trying to make an "onUpdate" function that loads the document that has been updated. Then I want to load another document using the data received by the wildcards. So to summarize I want to access the document that was updated and one more that is in the same collection.

I want : /userProfiles/{doc1}/employees/{doc2} AND /userProfiles/{doc1}.

I can get them both but when I try to use the data from one, it doesn't read the previous data and gives me a ReferenceError.

The end goal is to use both these docs to send an email with nodemailer. Thanks for any help.

const functions = require("firebase-functions");
const admin = require("firebase-admin");
const nodemailer = require('nodemailer');
admin.initializeApp();

exports.testLog = functions.firestore
  .document('/userProfiles/{doc1}/employees/{doc2}')
  .onUpdate((change, context) => {
    var info = [];
    const doc1 = context.params.doc1;
    const doc2 = context.params.doc2;

    const db = admin.firestore();

    return (
      db
        .collection("userProfiles")
        .doc(`${doc1}`)
        .get()
        .then(doc => {
          var email = doc.data().email;
          var phone = doc.data().phone;

          info.push(doc.data());

          console.log(email, phone); // sees and gets info

          return email, phone;
        }),
      db
        .collection("userProfiles")
        .doc(`${doc1}`)
        .collection(`employees`)
        .doc(`${doc2}`)
        .get()
        .then(doc => {
          info.push(doc.data());

          var Status = doc.data().Status;

          console.log(phone, `${Status}`); //phone is undefined

          if (`${Status}` === "Alarm") {
            // replace with variables from the users settings page

            console.log(`${info.phone}`); // phone is undefined

            let transporter = nodemailer.createTransport({
              host: "smtp.gmail.com",
              port: 587,
              secure: false, 
              auth: {
                user: "xxxxxx@gmail.com",
                pass: "xxxxxxxxxx"
              }
            });

            // send mail with defined transport object
            let mailOptions = {
              from: '"Fred Foo " <foo@example.com>', 
              to: `${info.phone}`,  // tried phone as well
              subject: "Hello ✔", 
              text: "216+?", 

            };

            transporter.sendMail(mailOptions, error => {
              if (error) {
                return console.log(error);
              } else {
                return console.log("message sent");
              }
            });
          }

          console.log(Status);
          // return
          return console.log("im after the if statement. No alarm triggered");
        })

        .then(message => console.log(message.sid, "success"))
        .catch(err => console.log(err))
    );
  });

So I want to get the phone number and the Status in these 2 images The error that is returned:

ReferenceError: phone is not defined

Answer 1

There are two things that aren't quite working the way you expect leading to your problem:

• The handling of promises isn't really passing data the way you expect -- in particular, the variables phone and email exist only in one promise handler, they aren't global in scope, so phone and email aren't being passed down the promise chain.

• You don't actually need to ever read the second document, as the content is passed to you in the function itself. This actually greatly simplifies the overall thing you are doing, and makes dealing with the first point nearly trivial, since you can skip the second database call.

Look at this code where I have omitted the messaging code for clarity and just left in place most of the log messages:

exports.firestoreOnUpdateTest = functions.firestore
    .document('/userProfiles/{doc1}/employees/{doc2}')
    .onUpdate((change, context) => {
  // var info = []; I have removed this list, it is not necessary
  const doc1 = context.params.doc1;
  // no need to get the doc2 parameter, as we are handed the doc itself by the function call.

  const doc2content = change.after.data();

  const db = admin.firestore();

  return (
    db
      .collection("userProfiles")
      .doc(`${doc1}`)
      .get()
      .then(doc => {
        const doc1content = doc.data();
        const email = doc1content.email;
        const phone = doc1content.phone;

        console.log(email, phone); // sees and gets info

        console.log(`No need to fetch doc2, as I already have it: ${JSON.stringify(doc2content)}`);
        const Status = doc2content.Status;

        console.log(`email for user is still: ${email}`); // email is now defined
        console.log(phone, `${Status}`); // phone is now defined

        if (`${Status}` === "Alarm") {
          console.log(`${phone}`); // phone is now defined

          return console.log('message would be sent here - code omitted')
        }

        console.log(Status);

        return console.log("im after the if statement. No alarm triggered");
      })
      .catch(err => console.error(err))
  );
});

In the new version, we just store the content from the document that triggered us, including the Status parameter. We then fetch the document with the content we need -- at the higher level in the tree. Once that document is returned, we just process it and combine with the data from doc2. All the fields are now defined (assuming, of course, the database objects are well-formed).

Your messaging code would be re-inserted right were the obvious log message is.

Finally, the info list I don't think is necessary now, so I've removed it. Instead, I recommend you build what you need as you construct the message itself from the data already on hand. That said, your original code wasn't accessing it correctly (that is, as a list) anyway and may have been confusing you further.

Finally, I haven't addressed the use of the Nodemailer module as the question focused primarily on the undefined fields, but I suspect your original code may not be entirely correct either -- as it doesn't either return a promise back from sendMail() or perform an await on that call (and make the entire function async), so you will need to look at that more closely.