How should I write a query for Firestore when I know that the number of document references returned will be only 1?
const query = firebase.firestore().collection('Users').where('mobile', '==', '<some mobile number>').limit(1);
To get the document from this query, I'm using the forEach loop. Is there any way to get the document and its data without using the loop?
let docId;
query.get().then((snapShot) => {
snapShot.forEach((doc) => {
docId = doc.id;
});
if(docId) {
// doc exists
// do something with the data...
}
}).catch((error) => console.log(error.message));
OK. I figured it out.
The .docs() method can be used on the snapShot object to get an array of all the documents refs matching the query.
So, if I only have a single document, I can simply access it as follows:
query.get().then((snapShot) => {
const doc = snapShot.docs[0];
const docId = doc.id;
const docData = doc.data();
// so stuff here...
}).catch((error) => console.log(error.message));
Related
I have some code that gets a collection reference to the users collection and then queries an animeID field whether it contains a certain value or not. I want to change this and only query inside the document with the id i pass. So if you look at the picture of my firestore you can see that i have two documents inside the users collection each with their unique id. I want to query for the animeID field only in the document that i want. Not all the documents as it does right now. How would i go about doing this? I have tried using doc and then passing in the id of the document but i don't think query works on doc as it gives me an error. Thanks
const docRef = collection(db, 'users')
const q = query(docRef, where('animeID', 'array-contains', parseInt(id)))
onSnapshot(q, (snapshot) => {
let results = []
snapshot.docs.forEach((doc) => {
results.push({...doc.data(), id: doc.id})
})
if(results.length > 0){
console.log(true)
}
else{
console.log(false)
}
}, (error) => {
console.log(error)
})
Firestore structure:
You need to do as explained in the doc:
import { doc, getDoc } from "firebase/firestore";
const docRef = doc(db, "users", "dbmbEiR6....");
const docSnap = await getDoc(docRef);
if (docSnap.exists()) {
const animeID = docSnap.data().animeID;
// Do whatever you want with animeID
// E.g. log its value:
console.log(JSON.stringify(animeID));
} else {
// doc.data() will be undefined in this case
console.log("No such document!");
}
So you don't need to declare a Query in this case. Just declare a DocumentReference and use the getDoc() method.
I'm trying to add a delete button to my page. the event listener callback is working properly except for the updateDoc function.
const deleteBook = document.getElementsByClassName('deleteBook');
for (let i = 0; i < deleteBook.length; i++) {
deleteBook[i].addEventListener('click', async () => {
//book to delete
const bookToDelete = deleteBook[i].parentElement.firstElementChild.textContent
// collection title to delete the book from
const bookCol = deleteBook[i].parentElement.parentElement.parentElement.firstElementChild.textContent
// get a snap of the database
const docRef = doc(dataBase, 'users', `${auth.currentUser.uid}`)
const docSnap = (await getDoc(docRef)).data();
// loop over the collections and get a match with the bookCol
for (const col in docSnap) {
if (docSnap[col].title === bookCol) {
console.log('col to delete from found')
console.log(`book to delete ${bookToDelete}`)
await updateDoc(doc(dataBase, 'users', `${auth.currentUser.uid}`), {
[`${col}.books`]: arrayRemove(`${bookToDelete}`)
}).then(()=>{
// fullfiled
console.log('book deleted')
}, ()=>{
// rejected
console.log('promis rejected')
})
}
}
})
}
Col is the object that contains the books array. In the console it always prints book deleted, but in the firestore console, nothing changes. this is a screenshot of the database.
I would really appreciate any help and thank you.
I have replicated the behavior that you're experiencing. I tried changing the content of ${bookToDelete} to any word or even ID. It always returns book deleted even if its deleted or not. The line of code below should be changed in order to get the correct output.
.then(()=>{
// fullfiled
console.log('book deleted')
}, ()=>{
// rejected
console.log('promis rejected')
})
I have created a workaround for your use-case with this kind of issue. See snippet below:
const db = getFirestore();
const colName = "users";
const arrayName = "books";
const usersCol = collection(db, colName);
const userRef = doc(db, colName, `${auth.currentUser.uid}`);
const arrayRef = `${col}.${arrayName}`;
const q = query(usersCol, where(arrayRef, "array-contains", `${bookToDelete}`));
const querySnapshot = await getDocs(q)
.then((querySnapshot) => {
// Removal of object will not proceed if the querySnapshot is empty.
if ((querySnapshot.empty)) {
console.log("No object found!");
}
else {
// Proceeds to removal of object.
updateDoc(userRef, {
[arrayRef]: arrayRemove(`${bookToDelete}`)
})
.then(() => {
// Check again if the object was deleted successfully.
const querySnapshot = getDocs(q)
.then((querySnapshot) => {
if ((querySnapshot.empty)) {
console.log("Book Deleted!");
}
else {
console.log("Failed!");
}
})
});
}
})
// Catch if there are any Firebase errors.
.catch(error => console.log('Failed!', error));
The workaround that I created will query the object in the array then remove the object in the array if it exist. After removing, it will query again to check if the object has been deleted and logs Book Deleted!. Vise versa for checking if the object doesn't exist on the 1st query, it will not proceed on removing them and logs No object found!.
The workaround itself can still be improved. You can add any logic you want for your use-case.
I'd also recommend to create a Feature Request if you want to have this kind of feature together with the arrayRemove Method.
I'm a novice when it comes to coding (started teaching myself ~year ago), any help will be much appreciated, thank you in advance.
I saw that there is 3-4 other post on stack overflow on how to access Firestore's sub-collections.
I tried them all and had no luck, hence why I'm posting this as a new question.
right now I have my data set is up as: collection/document.array. And that was fine till now because I just needed to read that data from the array to draw it out in my little React project with .reduce and .map and push new data to that array on input.
this is the code I have right now for getting data from Firestore:
--- in firebase.js ----------------------------------------------------------------------
export const fire = firebase.initializeApp(config);
export const db = fire.firestore()
_________________________________________________________________________________________
--- in events-context.js ----------------------------------------------------------------
const fetchEvents = async () => {
try {
const data = await db.collection('events').get();
setEvents(data.docs.map(doc => ({ ...doc.data(), id: doc.id })));
} catch ({ message }) {
alert(`Error # fetchEvents, Error:${message}`);
}
};
But now I want to add edit and a remove feature, but in order to do that, I need to carry out my array of data into a sub-collection so each individual element from that array had its own id so that I could later target it. so it needs to be set up something like this: collection/document/sub-collection
To access a document inside a collection, you must know the document ID from another source. This can be done by managing the names inside an array of strings or maps that you can then process within your app per your design.
For example: once created, you will have a snapshot of the reference of which you can store the document id inside the parent document:
db.collection("events").doc(id).update({
payers: firebase.firestore.FieldValue.arrayUnion(paySnapshot.ref.id)
})`
Once you have this information, you can append it to the relevant document path using one of the following techniques.
db.collection("events").doc(id).collection("payers").doc(pay_id).get()
db.doc(\events/${id}/payers/${pay_id}`).get()`
I strongly advise against using .get() on a collection without limit() and where() conditions to reduce the reads that can occur.
Try this, it works for me :)
Insert data >>>
const q = query(collection(this.fire, "events"));
const querySnapshot = await getDocs(q);
const queryData = querySnapshot.docs.map((details) => ({
...details.data(),
id: details.id,
}));
console.log(queryData);
queryData.map(async (v, id) => {
await setDoc(doc(this.fire, `events/${auth}/more`, events.title), {
'title': events.title,
'uid': auth,
//your data here
})
})
Read Data >>>
const querySnapshot = await getDocs(collection(this.fire,
`/events/${auth}/more/`)); querySnapshot.forEach((doc) => { //
doc.data() is never undefined for query doc snapshots
console.log(doc.id, " => ", doc.data()); });
return querySnapshot;
I am querying firebase firestore by...
let database = firebase.firestore();
let places = database.collection("place");
console.log("places", places);
now the logged data is bizarre and not the actual documents..
here is a picture of the log...can you please advice regarding tackling this ?
If you want to retrieve all items in your collections called "place" you can do something like this:
let database = firebase.firestore();
let places = database.collection("place");
const querySnapshot = places.get()
// You can make an empty array to eventually push the items into
const collectionArray = []
querySnapshot.forEach((doc) => {
const data = doc.data()
collectionArray.push(data)
}).catch(function(error) {
console.log("Error getting documents: ", error);
})
console.log('collectionArray:',collectionArray)
}
Your code hasn't actually executed any query yet. All it's done is build a Query object.
If you want to execute the query, call get() on it, and handle the results as shown in the documentation.
let database = firebase.firestore();
let query = database.collection("place");
query.get()
.then(querySnapshot => {
querySnapshot.forEach(documentSnapshot => {
console.log("document", documentSnapshot.data());
})
})
I need help, i'm trying to update my comments collections using cloud function, but my code doesn't seem to work. My function succesfully run but doesn't update my avatarUrl when my userPhotoUrl is update
Here the whole path of the collection that i want to update : "/comments/{postId}/comments/{commentId}"
my firestore collection
exports.onUpdateUser2 = functions.firestore
.document("/users/{userId}")
.onUpdate(async (change, context) => {
const userUpdate = change.after.data();
const userId = context.params.userId;
const newPhotoUrl = userUpdate.photoUrl;
console.log("userId",userId);
console.log("newPhotoUrl",newPhotoUrl);
const querySnapshot = await admin.firestore().collection("comments").get();
querySnapshot.forEach(doc => {
console.log("doc",doc.data());
const postId = doc.id;
const comments = admin.firestore().collection("comments").doc(postId).collection("comments").where("userId","==",userId).get();
comments.forEach(doc2 => {
return doc2.ref.update({avatarUrl: newPhotoUrl});
});
});
});
Thank you,
UPDATE
I try to change the code, by using then to deal with these various promises but i don't really know why commentsRef.get() seem to return me empty querySnapshots, because the comments collections in my firestore database have multiple documents where in each documents there is a another comments collections where in this seconds comments collections there is a bunch of documents containing data. With this whole path i don't know how to iterate until being in the documents containing the data that i need to update. Can someone help me please ?
exports.onUpdateUserUpdateComments = functions.firestore
.document("/users/{userId}")
.onUpdate(async (change, context) => {
const userUpdate = change.after.data();
const userId = context.params.userId;
const newPhotoUrl = userUpdate.photoUrl;
console.log("userId",userId);
console.log("newPhotoUrl",newPhotoUrl);
const commentsRef= admin.firestore().collection("comments");
return commentsRef.get().then(querySnapshot => {
return querySnapshot.forEach(doc => {
return admin
.firestore()
.collection("comments")
.doc(postId)
.collection("comments")
.where("userId", "==", userId)
.get()
.then(doc => {
if (doc.exists) {
doc.ref.update({avatarUrl: newPhotoUrl});
}
return console.log("The function has been run.");
});
});
});
});
Without trying it, it should be something like this:
return admin.firestore().collection("comments")
.doc(postId)
.where("userId", "==", userId)
.get()
.then(doc => {
if (doc.exists) {
doc.ref.update({avatarUrl: newPhotoUrl});
}
return console.log("The function has been run.");
});
Regardless, following Doug Stevenson's advice, you shouldn't start learning JS in Cloud Functions, as those nested loops are a bit strange and you may lack a good starting point for learning.