how to remove an array item from firestore using JavaScript? - javascript

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.

Related

My firebase function update document takes MINUTES to execute the first time

I am developping an app to order food online. As backend service I am using firestore to store the data and files. The user can order dishes and there are limited stocks. So every time a user order a dish and create a basket I update the stock of the corresponding ordered dishes. I am using a firebase function in order to perform this action. To be honest it is the first I am creating firebase function.
Into the Basket object, there is a list of ordered Dishes with the corresponding database DishID. When the basket is created, I go through the DishID list and I update the Quantity in the firestore database. On my local emulator it works perfectly and very fast. But online it takes minutes to perform the first update. I can deal with some seconds. Even if it takes a few seconds (like for cold restart) it's okay. But sometimes it can take 3 minutes and someone else can order a dish during this time.
Here is my code:
//Update the dishes quantities when a basket is created
exports.updateDishesQuantity = functions.firestore.document('/Baskets/{documentId}').onCreate(async (snap, context) => {
try{
//Get the created basket
const originalBasket = snap.data();
originalBasket.OrderedDishes.forEach(async dish => {
const doc = await db.collection('Dishes').doc(dish.DishID);
console.log('Doc created');
return docRef = doc.get()
.then((result) =>{
console.log('DocRef created');
if(result.exists){
console.log('Result exists');
const dishAvailableOnDataBase = result.data().Available;
console.log('Data created');
const newQuantity = { Available: Math.max(dishAvailableOnDataBase - dish.Quantity, 0)};
console.log('Online doc updated');
return result.ref.set(newQuantity, { merge: true });
}else{
console.log("doc doesnt exist");
}
})
.catch(error =>{
console.log(error);
return null;
});
});
}catch(error){
console.log(error);
}
});
I have a couple of logs output to debug the outputs on the server. It's the doc.get() function that takes 2 minutes to execute as you can see on the logger below:
Firebase logger
Thanks for your help,
Thansk for your help. I just edited a little bit your code to make it work. I post my edited code. Thanks a lot, now it takes just 4 seconds to update the quantities.
Kid regards
//Update the dishes quantities when a basket is created
exports.updateDishesQuantity = functions.firestore.document('/Baskets/{documentId}').onCreate(async (snap, context) => {
try {
//Get the created basket
const originalBasket = snap.data();
const promises = [];
const quantities = [];
originalBasket.OrderedDishes.forEach(dish => {
promises.push(db.collection('Dishes').doc(dish.DishID).get());
quantities.push(dish.Quantity);
});
const docSnapshotsArray = await Promise.all(promises);
console.log("Promises", promises);
const promises1 = [];
var i = 0;
docSnapshotsArray.forEach(result => {
if (result.exists) {
const dishAvailableOnDataBase = result.data().Available;
const newQuantity = { Available: Math.max(dishAvailableOnDataBase - quantities[i], 0) };
promises1.push(result.ref.set(newQuantity, { merge: true }));
}
i++;
})
return Promise.all(promises1)
} catch (error) {
console.log(error);
return null;
}
});
You should not use async/await within a forEach() loop, see "JavaScript: async/await with forEach()" and "Using async/await with a forEach loop".
And since your code executes, in parallel, a variable number of calls to the asynchronous Firebase get() and set() methods, you should use Promise.all().
You should refactor your Cloud Function along the following lines:
//Update the dishes quantities when a basket is created
exports.updateDishesQuantity = functions.firestore.document('/Baskets/{documentId}').onCreate(async (snap, context) => {
try {
//Get the created basket
const originalBasket = snap.data();
const promises = [];
originalBasket.OrderedDishes.forEach(dish => {
promises.push(db.collection('Dishes').doc(dish.DishID).get());
});
const docSnapshotsArray = await Promise.all(promises);
const promises1 = [];
docSnapshotsArray.forEach(snap => {
if (result.exists) {
const dishAvailableOnDataBase = result.data().Available;
const newQuantity = { Available: Math.max(dishAvailableOnDataBase - dish.Quantity, 0) };
promises1.push(result.ref.set(newQuantity, { merge: true }));
}
})
return Promise.all(promises1)
} catch (error) {
console.log(error);
return null;
}
});
Note that instead of looping and calling push() you could use the map() method for a much concise code. However, for SO answers, I like the clarity brought by creating an empty array, populating it with a forEach() loop and passing it to Promise.all()...
Also note that since you are updating quantities in a basket you may need to use a Transaction.

How to query in a specific document in Firebase

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.

Unable to batch.delete documents of a subcollection

I have a collection called display and each document inside the display has a subcollection called history. There's no error, though, it does not delete the documents in Firestore. After selecting the row to be deleted, it is gone when you click delete. However, once you reload the screen, the data deleted was still there, meaning it wasn't successfully deleted in Firestore.
I recreated the error I have in the code sandbox: https://codesandbox.io/s/batch-delete-not-working-vcqcd3?file=/src/App.js
async function batchDeleteDocuments(docID, historyId) {
try {
console.log(docID, "docs");
console.log(historyId, "history");
const batch = writeBatch(db);
for (let i = 0; i < docID.length; i++) {
const docRef = doc(db, "display", docID[i], "history", historyId[i]);
console.log(i, "deleting", docRef.path);
batch.delete(docRef);
}
await batch.commit();
console.log("deleted");
} catch (err) {
console.log(err);
}
}
Upon checking your codesandbox, the field docID has whitespace at the beginning of the string. See screenshot of your codesandbox logs:
Digging deeper into your code, I've found no issues with how you fetch your data. It's just that when you try to log your doc.data() in this query:
const getUsers = async () => {
const listUsers = query(collectionGroup(db, "history"));
const querySnapshot = await getDocs(listUsers);
const arr = [];
querySnapshot.forEach((doc) => {
console.log(doc.id, " => ", doc.data());
arr.push({
...doc.data(),
id: doc.id
});
});
if (isMounted) {
setUsers(arr);
}
};
The value of docID on your document has whitespace on it. Check the values of docID in your documents of the history collection and make sure that you removed all the whitespace on it.
I also tried to replace the docID[i] in this query and successfully deleted the document.
// Try to change docID[i] to hard-coded value.
const docRef = doc(db, "display", "Tv9xj0pC9wTjr59MPsJw", "history", historyId[i]);
You can also use the trim() method for the workaround. See code below:
for (let i = 0; i < docID.length; i++) {
console.log(docID[i].trim());
const docRef = doc(
db,
"display",
docID[i].trim(),
"history",
historyId[i]
);
console.log(i, "deleting", docRef.path);
batch.delete(docRef);
}

Trouble batch setting a document field by docId in Firestore

I have been using firebase (firestore) for a while but I'm a little stuck and was wondering if anyone can think of a solution.
On the firestore DB I have a single collection of users, each user has an email address and several other fields. In this instance I am checking if a user email exists and if it does, I want to create a list field for that particular user with a listUid. I am referencing the users by email, grabbing the docId for those users and then trying to set a list field for each of them.
I am not getting any error's from firestore, it's simply not updating in the DB for some reason and I can't figure out where I am going wrong. Thanks in advance
export const addListUidToExistingUserList = (
{ firestore },
emailArray,
listUid
) => {
return async () => {
let docIds = [];
emailArray.forEach((emailAddress) => {
//find users by email (works)
const query = db
.collection("users")
.where("email", "==", emailAddress);
//get docId's for user with matching email (works)
query.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
docIds.push(doc.id);
});
});
//add a new list with corresponding listUid (does not work)
docIds.forEach((id) => {
let userRef = db.collection("users").doc(id);
batch.set(userRef, { lists: [{ listUid }] });
});
});
return await batch.commit();
};
};
You are running into this issue because your docIds array is always empty at the time you call docIds.forEach.
That's because query.get().then runs asynchronously, and so docIds.forEach is not waiting for it to complete.
You could either:
await query.get().then; or
Add the docIds.forEach function INSIDE the then callback of query.get.
Here are your possible fixes:
await query.get().then
//get docId's for user with matching email (works)
await query.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
docIds.push(doc.id);
});
});
OR:
docIds.forEach inside then
//get docId's for user with matching email (works)
query.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
docIds.push(doc.id);
});
docIds.forEach((id) => {
let userRef = db.collection("users").doc(id);
batch.set(userRef, { lists: [{ listUid }] });
});
});
Note: Of course, you could also add batch.set directly into your first iteration of querySnapshot.docs.forEach to prevent an unnecessary iteration.

What is going wrong with my express call? I need an array of ID's but its returning an empty array

Im guessing this problem is because I don't know how to use async await effectively. I still dont get it and I've been trying to understand for ages. sigh.
Anyway, heres my function:
app.post("/declineTrades", async (request, response) => {
//---------------------------------------------
const batch = db.batch();
const listingID = request.body.listingID;
const tradeOfferQuery = db
//---------------------------------------------
//Get trade offers that contain the item that just sold
//(therefore it cannot be traded anymore, I need to cancel all existing trade offers that contain the item because this item isn't available anymore)
//---------------------------------------------
.collection("tradeOffers")
.where("status", "==", "pending")
.where("itemIds", "array-contains", listingID);
//---------------------------------------------
//Function that gets all trade offers that contain the ID of the item.
async function getIdsToDecline() {
let tempArray = [];
tradeOfferQuery.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
//For each trade offer found
let offerRef = db.collection("tradeOffers").doc(doc.id);
//Change the status to declined
batch.update(offerRef, { status: "declined" });
//Get the data from the trade offer because I want to send an email
//to the who just got their trade offer declined.
const offerGet = offerRef.get().then((offer) => {
const offerData = offer.data();
//Check the items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
offerData.receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
//if the receiver item id's array includes this item that just sold, I know that
//I can get the sender ID (users can be sender or receiver, so i need to check which person is which)
if (receiverItemIds.includes(listingID)) {
tempArray.push(offerData.senderID);
}
});
});
});
//With the ID's now pushed, return the tempArray
return tempArray;
}
//---------------------------------------------
//Call the above function to get the ID's of people that got declined
//due to the item no longer being available
const peopleToDeclineArray = await getIdsToDecline();
//Update the trade offer objects to declined
const result = await batch.commit();
//END
response.status(201).send({
success: true,
result: result,
idArray: peopleToDeclineArray,
});
});
Im guessing that my return tempArray is in the wrong place? But I have tried putting it in other places and it still returns an empty array. Is my logic correct here? I need to run the forEach loop and add to the array before the batch.commit happens and before the response is sent.
TIA Guys!
As #jabaa pointed out in their comment, there are problems with an incorrectly chained Promise in your getIdsToDecline function.
Currently the function initializes an array called tempArray, starts executing the trade offer query and then returns the array (which is currently still empty) because the query hasn't finished yet.
While you could throw in await before tradeOfferQuery.get(), this won't solve your problem as it will only wait for the tradeOfferQuery to execute and the batch to be filled with entries, while still not waiting for any of the offerRef.get() calls to be completed to fill the tempArray.
To fix this, we need to make sure that all of the offerRef.get() calls finish first. To get all of these documents, you would use the following code to fetch each document, wait for all of them to complete and then pull out the snapshots:
const itemsToFetch = [ /* ... */ ];
const getAllItemsPromise = Promise.all(
itemsToFetch.map(item => item.get())
);
const fetchedItemSnapshots = await getAllItemsPromise;
For documents based on a query, you'd tweak this to be:
const querySnapshot = /* ... */;
const getSenderDocPromises = [];
querySnapshot.forEach((doc) => {
const senderID = doc.get("senderID");
const senderRef = db.collection("users").doc(senderID);
getSenderDocPromises.push(senderRef.get());
}
const getAllSenderDocPromise = Promise.all(getSenderDocPromises);
const fetchedSenderDataSnapshots = await getAllSenderDocPromise;
However neither of these approaches are necessary, as the document you are requesting using these offerRef.get() calls are already returned in your query so we don't even need to use get() here!
(doc) => {
let offerRef = db.collection("tradeOffers").doc(doc.id);
//Change the status to declined
batch.update(offerRef, { status: "declined" });
//Get the data from the trade offer because I want to send an email
//to the who just got their trade offer declined.
const offerGet = offerRef.get().then((offer) => {
const offerData = offer.data();
//Check the items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
offerData.receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
//if the receiver item id's array includes this item that just sold, I know that
//I can get the sender ID (users can be sender or receiver, so i need to check which person is which)
if (receiverItemIds.includes(listingID)) {
tempArray.push(offerData.senderID);
}
});
}
could be replaced with just
(doc) => {
// Change the status to declined
batch.update(doc.ref, { status: "declined" });
// Fetch the IDs of items that the receiving person had in this trade offer
const receiverItemIds = Array.from(
doc.get("receiversItems") // <-- this is the efficient form of doc.data().receiversItems
.reduce((set, { itemID }) => set.add(itemID), new Set())
.values()
);
// If the received item IDs includes the listed item, add the
// sender's ID to the array
if (receiverItemIds.includes(listingID)) {
tempArray.push(doc.get("senderID"));
}
}
which could be simplified to just
(doc) => {
//Change the status to declined
batch.update(doc.ref, { status: "declined" });
// Check if any items that the receiving person had in this trade offer
// include the listing ID.
const receiversItemsHasListingID = doc.get("receiversItems")
.some(item => item.itemID === listingID);
// If the listing ID was found, add the sender's ID to the array
if (receiversItemsHasListingID) {
tempArray.push(doc.get("senderID"));
}
}
Based on this, getIdsToDecline actually queues declining the invalid trades and returns the IDs of those senders affected. Instead of using the batch and tradeOfferQuery objects that are outside of the function that make this even more unclear, you should roll them into the function and pull it out of the express handler. I'll also rename it to declineInvalidTradesAndReturnAffectedSenders.
async function declineInvalidTradesAndReturnAffectedSenders(listingID) {
const tradeOfferQuery = db
.collection("tradeOffers")
.where("status", "==", "pending")
.where("itemIds", "array-contains", listingID);
const batch = db.batch();
const affectedSenderIDs = [];
const querySnapshot = await tradeOfferQuery.get();
querySnapshot.forEach((offerDoc) => {
batch.update(offerDoc.ref, { status: "declined" });
const receiversItemsHasListingID = offerDoc.get("receiversItems")
.some(item => item.itemID === listingID);
if (receiversItemsHasListingID) {
affectedSenderIDs.push(offerDoc.get("senderID"));
}
}
await batch.commit(); // generally, the return value of this isn't useful
return affectedSenderIDs;
}
This then would change your route handler to:
app.post("/declineTrades", async (request, response) => {
const listingID = request.body.listingID;
const peopleToDeclineArray = await declineInvalidTradesAndReturnAffectedSenders(listingID);
response.status(201).send({
success: true,
result: result,
idArray: peopleToDeclineArray,
});
});
Then adding the appropriate error handling, swapping out the incorrect use of HTTP 201 Created for HTTP 200 OK, and using json() instead of send(); you now get:
app.post("/declineTrades", async (request, response) => {
try {
const listingID = request.body.listingID;
const affectedSenderIDs = await declineInvalidTradesAndReturnAffectedSenders(listingID);
response.status(200).json({
success: true,
idArray: affectedSenderIDs, // consider renaming to affectedSenderIDs
});
} catch (error) {
console.error(`Failed to decline invalid trades for listing ${listingID}`, error);
if (!response.headersSent) {
response.status(500).json({
success: false,
errorCode: error.code || "unknown"
});
} else {
response.end(); // forcefully end corrupt response
}
}
});
Note: Even after all these changes, you are still missing any form of authentication. Consider swapping the HTTPS Event Function out for a Callable Function where this is handled for you but requires using a Firebase Client SDK.

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