firebase firestore从document-js获取对象/数组

Question

My firestore database currently looks like this: firestore db

how can I get the value of, say, DEVICES/ID. currently my code returns undefined when i try to get the value.

var userDeviceRef = db.collection("USERS").doc(data.uid);
userDeviceRef.get().then(function(doc){
    if (doc.exists) {
        console.log("Document data:", doc.data());
        console.log("document customdata foo: " + doc.data().DEVICES.ID);
    }
}

data.uid returns a proper value. the value of the document ID. doc.data() returns all the fields and its children in what appears to be string format. however when I add DEVICES.ID , it returns undefined. how can i get the nested data as shown in the image?

Answer 1

Your field called DEVICES is actually an array. As far as I can tell, it has at least one element in it. If you want the value of the ID field of the first element of that array, you'll have to index into that array:

doc.data().DEVICES[0].ID