How can I get specific document data from firestore querysnapshot? - firebase

Question

I got a querysnapshot in a function.
And want to bring the whole querysnapshot to another function (functionTwo).
In functionTwo, I want to get a specific document in the querysnapshot WITHOUT forEach. The specific doc can be changed by different cases.
ref_serial_setting.get()
.then(querysnapshot => {
return functionTwo(querysnapshot)
})
.catch(err => {
console.log('Error getting documents', err)
})
let functionTwo = (querysnapshot) => {
// getting value
const dataKey_1 = "dataKey_1"
// Tried 1
const value = querysnapshot.doc(dataKey_1).data()
// Tried 2
const value = querysnapshot.document(dataKey_1).data()
// Tried 3 (Put 'data_name': dataKey_1 in that doc)
const value = querysnapshot.where('data_name', '==', dataKey_1).data()
}
The result are all these trying are not a function.
How can I get specific document data from querysnapshot??
or
Is there any easy method to change the querysnapshot to JSON?

Answer 1

You can get an array of the document snapshots by using the docs property of a QuerySnapshot. After that you'll have to loop through getting the data of the doc snapshots looking for your doc.
const docSnapshots = querysnapshot.docs;
for (var i in docSnapshots) {
const doc = docSnapshots[i].data();
// Check for your document data here and break when you find it
}
Or if you don't actually need the full QuerySnapshot, you can apply the filter using the where function before calling get on the query object:
const dataKey_1 = "dataKey_1";
const initialQuery = ref_serial_setting;
const filteredQuery = initialQuery.where('data_name', '==', dataKey_1);
filteredQuery.get()
.then(querySnapshot => {
// If your data is unique in that document collection, you should
// get a query snapshot containing only 1 document snapshot here
})
.catch(error => {
// Catch errors
});

Answer 2

Theres an easy way to do this, each QuerySnapshot has a property docs which returns an array of QueryDocumentSnapshots. See QuerySnapshot documentation.
let citiesRef = db.collection('cities');
let query = citiesRef.where('capital', '==', true).get().then(snapshot => {
snapshot.docs[0]; // => returns first document
});

Answer 3

let citiesRef = db.collection('cities');
let query = citiesRef.where('capital', '==', true).get()
.then(snapshot => {
if (snapshot.empty) {
console.log('No matching documents.');
return;
}
snapshot.forEach(doc => {
console.log(doc.id, '=>', doc.data());
});
})
.catch(err => {
console.log('Error getting documents', err);
});
from https://firebase.google.com/docs/firestore/query-data/get-data

Answer 4

you can use this code :
const querySnapshot = await getDocs(collection(db, "collectionNaame"));
const docSnapshots = querySnapshot.docs;
for (var i in docSnapshots) {
console.log(i)
const doc = docSnapshots[i].data();
console.log(doc)

Answer 5

Just do
db.doc(<<ref>>).get()
this returns a promise
[here ]: https://firebase.google.com/docs/firestore/query-data/get-data#get_a_document is the link to the docs