Firebase Functions won't read document on Firestore - node.js

Question

Hi I'm trying to read a users document stored on Firestore using Firebase Functions. Each user has a unique document with extra data that cannot be stored on Firebase Auth. The document name is the user UID.
But I can't access the doc when I'm trying to read it on my callable function.
Code to create doc when user is created:
exports.createdacc = functions.auth.user().onCreate(user => {
console.log('User created', user.phoneNumber);
return admin.firestore().collection('users').doc(user.uid).set({
number: user.phoneNumber,
verified: false,
});
});
Callable function to read that doc so I can make some decisions
exports.checkVerification = functions.https.onCall((data, context) => {
if (!context.auth){
throw new functions.https.HttpsError('unauthenticated');
}
console.log('user is ', context.auth.uid);
const user = admin.firestore().collection('users').doc(context.auth.uid);
user.get().then(doc => {
//temp code -- Not working
console.log('data read');
if (doc.get().verified){
console.log('verified');
} else {
console.log('not verified');
}
return "success";
}).catch(error => {
throw new functions.https.HttpsError('internal');
});
});
Why cant I read the doc? Nothing inside there executes.

Answer 1

Try to use data() at callback of user.get()
user.get().then(doc => {
//you get user doc value by using data()
const userData = doc.data();
// then you can use all properties from userData
const verified = userData.verified;
});

Answer 2

You don't return the promise returned by user.get().then(...);: your Cloud Function may be cleaned up before the asynchronous work is complete and the response sent back to the front-end.
Note that doing doc.get().verified is incorrect: as you will see in the doc, you need to pass the field path of a specific field to this method. So either you do doc.get("verified") or you can do doc.data().verified;.
Therefore the following should work:
exports.checkVerification = functions.https.onCall((data, context) => {
if (!context.auth) {
throw new functions.https.HttpsError('unauthenticated');
}
console.log('user is ', context.auth.uid);
const user = admin.firestore().collection('users').doc(context.auth.uid);
return user.get().then(doc => {
console.log('data read');
if (doc.get("verified") {
console.log('verified');
} else {
console.log('not verified');
}
return "success";
}).catch(error => {
throw new functions.https.HttpsError('internal');
});
});
In addition, note that you may throw an error if the user document does not exist and return a specific error to the front-end, i.e. not the generic internal one (maybe not-found, see the list of possible codes).

Answer 3

I have seen, on occasion, that information coming in to the function via context and data are actually JSON, and not strictly a standard Javascript object. In a similar issue of matching (in my case, a customClaim on the context.auth.token), I had to do something like:
JSON.parse(JSON.stringify(context.auth.token.customCLaim))
They behave like an object (i.e. I can call/assign context.auth.token.customClaim), but results from a console.log are different.
console.log(context.auth.token.customCLaim);
//prints {"userID": "1234567890"}
console.log(JSON.parse(JSON.stringify(context.auth.token.customClaim)));
//prints {userID: "1234567890"}
Subtle, but it tripped me up in a few authentication cases.