CODEWITHSUNDEEP
firebasegoogle-cloud-firestoregoogle-cloud-functions
Ferda Nahit FIDANCI
Ferda Nahit FIDANCI

Reputation: 379

Accessing a collection inside of a document in firestore

I have a document, and inside of it there is a collection called relatives. In cloud functions, I have onUpdate() listener for this document. Once something is changed, I want to access that collection inside of my document. Also documents in the collection relatives.

Here is how it looks like:

enter image description here

What I have tried

exports.UpdateLocations = functions.firestore.document("users/{userID}").onUpdate((change, context) => {
    const userEmail = change.after.data().email;
    const prevLocation = change.before.data().userLocation;
    const currentLocation = change.after.data().userLocation;

    if (prevLocation === currentLocation) return 0;

    if (change.after.data().userType.toString() === "Patient") {
        const userLocation = change.after.data().userLocation;
        const relatives = change.after.data().relatives;

        console.log("User's Current Location: " + userLocation);
        console.log("Relatives : "+relatives );

    }
    return;

});

I want to access relatives and its documents. So I can search and compare field and update them on purpose.

Upvotes: 1

Views: 2073

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 598688

To get a subcollection from a DocumentSnapshot, you must first get a DocumentReference to the document for that snapshot, and then find the CollectionReference under that.

In code:

change.after.ref.collection("relatives")

In here:

  1. change.after gives you the DocumentSnapshot of the modified document.
  2. change.after.ref then gives you the DocumentReference of that document, so its location in the database.
  3. change.after.ref.collection("relatives") then gives you the CollectionReference to the relatives subcollection of the document.

So get data from these subcollections you'll have to actually load that data, it is not already included in the change object that is passed to your function.

So if you want to load all relatives for the user that triggered the function, it'd be something like:

let relativesRef = change.after.ref.collection("relatives");
return relatives.get().then((querySnapshot) => {
  querySnapshot.forEach((relativeDoc) => {
    console.log(doc.id, doc.data().relativeaccount);
  });
});

Upvotes: 2

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