I have this data from firestore and I wanted to retrieve it dynamically with a where() but this is the error I'm getting:
TypeError: vaccines is not a function
The user collection:
[![enter image description here][1]][1]
Below are the codes:
const Vaccine = () => {
const [vaccines, setVaccines] = useState([]);
useEffect(() => {
const unsubscribe = firestore
.collection("vaccines")
.onSnapshot((snapshot) => {
const arr = [];
snapshot.forEach((doc) =>
arr.push({
...doc.data(),
id: doc.id,
})
);
setVaccines(arr);
});
return () => {
unsubscribe();
};
}, []);
Preface
As highlighted in the comments on the original question, this query structure is not advised as it requires read access to sensitive user data under /users that includes private medical data.
DO NOT USE THIS CODE IN A PRODUCTION/COMMERICAL ENVIRONMENT. Failure to heed this warning will lead to someone suing you for breaches of privacy regulations.
It is only suitable for a school project (although I would a fail a student for such a security hole) or proof of concept using mocked data. The code included below is provided for education purposes, to solve your specific query and to show strategies of handling dynamic queries in React.
From a performance standpoint, in the worst case scenario (a cache miss), you will be billed one read, for every user with at least one dose of any vaccine, on every refresh, for every viewing user. Even though your code doesn't use the contents of any user document, your code must download all of this data too because the Client SDKs do not support the select() operator.
For better security and performance, perform this logic server-side (e.g. Cloud Function, a script on your own computer, etc) and save the results to a single document that can be reused by all users. This will allow you to properly tighten access to /users. It also significantly simplifies the code you need to display the graphs and live statistics on the client-side.
useEffect
As stated by the React documentation on the Rules of hooks:
Only Call Hooks at the Top Level
Don’t call Hooks inside loops, conditions, or nested functions. Instead, always use Hooks at the top level of your React function, before any early returns. By following this rule, you ensure that Hooks are called in the same order each time a component renders. That’s what allows React to correctly preserve the state of Hooks between multiple useState and useEffect calls.
The documentation further elaborates that React relies on the order in which Hooks are called, which means that you can't have hook definitions behind conditional logic where their order and quantity changes between renders. If your hooks rely on some conditional logic, it must be defined inside of the hook's declaration.
As an example, if you have an effect that relies on other data, with this logic:
const [userProfile, setUserProfile] = useState();
const [userPosts, setUserPosts] = useState(null);
useEffect(() => {
// get user profile data and store in userProfile
}, []);
if (userProfile) {
useEffect(() => {
// get user post list and store in userPosts
}, [userProfile]);
}
you need to instead use:
const [userProfile, setUserProfile] = useState();
const [userPosts, setUserPosts] = useState(null);
useEffect(() => {
// get user profile data and store in userProfile
}, []);
useEffect(() => {
if (!userProfile) {
// not ready yet/signed out
setUserPosts(null);
return;
}
// get user post list and store in userPosts
}, [userProfile]);
Similarly, for arrays:
someArray && someArray.forEach((entry) => {
useEffect(() => {
// do something with entry to define the effect
}, /* variable change hooks */);
});
should instead be:
useEffect(() => {
if (!someArray) {
// not ready yet
return;
}
const cleanupFunctions = [];
someArray.forEach((entry) => {
// do something with entry to define an effect
cleanupFunctions.push(() => {
// clean up the effect
});
});
// return function to cleanup the effects created here
return () => {
cleanupFunctions.forEach(cleanup => cleanup());
}
}, /* variable change hooks */);
Because this looks a lot like lifecycle management, you are actually better off replacing it with nested components rather than using hooks, like so:
return (
<> // tip: React.Fragment shorthand (used for multiple top-level elements)
{
someArray && someArray
.map(entry => {
return <Entry key={entry.key} data={entry.data} />
})
}
</>
);
Adapting to your code
Note: The code here doesn't use onSnapshot for the statistics because it would cause a rerender every time a new user is added to the database.
const getVaccineStats = (vaccineName) => {
const baseQuery = firestore
.collection("users")
.where("doses.selectedVaccine", "==", vaccine);
const oneDoseQueryPromise = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", false)
.get()
.then(querySnapshot => querySnapshot.size);
const twoDoseQueryPromise = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", true)
.get()
.then(querySnapshot => querySnapshot.size);
return Promise.all([oneDoseQueryPromise, twoDoseQueryPromise])
.then(([oneDoseCount, twoDoseCount]) => ({ // tip: used "destructuring syntax" instead of `results[0]` and `results[1]`
withOneDose: oneDoseCount,
withTwoDoses: twoDoseCount
}));
};
const Vaccine = () => {
const [vaccines, setVaccines] = useState();
const [vaccineStatsArr, setVaccineStatsArr] = useState([]);
// Purpose: Collect vaccine definitions and store in `vaccines`
useEffect(() => {
return firestore // tip: you can return the unsubscribe function from `onSnapshot` directly
.collection("vaccines")
.onSnapshot({ // tip: using the Observer-like syntax, allows you to handle errors
next: (querySnapshot) => {
const vaccineData = []; // tip: renamed `arr` to indicate what the data contains
querySnapshot.forEach((doc) =>
vaccineData.push({
...doc.data(),
id: doc.id,
});
);
setVaccines(vaccineData);
}),
error: (err) => {
// TODO: Handle database errors (e.g. no permission, no connection)
}
});
}, []);
// Purpose: For each vaccine definition, fetch relevant statistics
// and store in `vaccineStatsArr`
useEffect(() => {
if (!vaccines || vaccines.length === 0) {
return; // no definitions ready, exit early
}
const getVaccineStatsPromises = vaccines
.map(({ vaccine }) => [vaccine, getVaccineStats(vaccine)]);
// tip: used "destructuring syntax" on above line
// (same as `.map(vaccineInfo => [vaccineInfo.vaccine, getVaccineStats(vaccineInfo.vaccine)]);`)
let unsubscribed = false;
Promise.all(getVaccineStatsPromises)
.then(newVaccineStatsArr => {
if (unsubscribed) return; // unsubscribed? do nothing
setVaccineStatsArr(newVaccineStatsArr);
})
.catch(err => {
if (unsubscribed) return; // unsubscribed? do nothing
// TODO: handle errors
});
return () => unsubscribed = true;
}, [vaccines]);
if (!vaccines) // not ready? hide element
return null;
if (vaccines.length === 0) // no vaccines found? show error
return (<span class="error">No vaccines found in database</span>);
if (vaccineStatsArr.length === 0) // no stats yet? show loading message
return (<span>Loading statistics...</span>);
return (<> // tip: React.Fragment shorthand
{
vaccineStatsArr.map(([name, stats]) => {
// this is an example component, find something suitable
// the `key` property is required
return (<BarGraph
key={name}
title={`${name} Statistics`}
columns={["One Dose", "Two Doses"]}
data={[stats.withOneDose, stats.withTwoDoses]}
/>);
});
}
</>);
};
export default Vaccine;
Live Statistics
If you want your graphs to be updated live, you need "zip together" the two snapshot listeners into one, similar to the rxjs combineLatest operator. Here is an example implementation of this:
const onVaccineStatsSnapshot => (vaccine, observerOrSnapshotCallback, errorCallback = undefined) => {
const observer = typeof observerOrCallback === 'function'
? { next: observerOrSnapshotCallback, error: errorCallback }
: observerOrSnapshotCallback;
let latestWithOneDose,
latestWithTwoDoses,
oneDoseReady = false,
twoDosesReady = false;
const fireNext = () => {
// don't actually fire event until both counts have come in
if (oneDoseReady && twoDosesReady) {
observer.next({
withOneDose: latestWithOneDose,
withTwoDoses: latestWithTwoDoses
});
}
};
const fireError = observer.error || (err) => console.error(err);
const oneDoseUnsubscribe = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", false)
.onSnapshot({
next: (querySnapshot) => {
latestWithOneDose = querySnapshot.size;
oneDoseReady = true;
fireNext();
},
error: fireError
});
const twoDoseUnsubscribe = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", true)
.onSnapshot({
next: (querySnapshot) => {
latestWithTwoDoses = querySnapshot.size;
twoDosesReady = true;
fireNext();
},
error: fireError
});
return () => {
oneDoseUnsubscribe();
twoDoseUnsubscribe();
};
}
You could rewrite the above function to make use of useState, but this would unnecessarily cause components to rerender when they don't need to.
Usage (direct):
const unsubscribe = onVaccineStatsSnapshot(vaccineName, {
next: (statsSnapshot) => {
// do something with { withOneDose, withTwoDoses } object
},
error: (err) => {
// TODO: error handling
}
);
or
const unsubscribe = onVaccineStatsSnapshot(vaccineName, (statsSnapshot) => {
// do something with { withOneDose, withTwoDoses } object
});
Usage (as a component):
const VaccineStatsGraph = (vaccineName) => {
const [stats, setStats] = useState(null);
useEffect(() => onVaccineStatsSnapshot(vaccineName, {
next: (newStats) => setStats(newStats),
error: (err) => {
// TODO: Handle errors
}
}, [vaccineName]);
if (!stats)
return (<span>Loading graph for {vaccineName}...</span>);
return (
<BarGraph
title={`${name} Statistics`}
columns={["One Dose", "Two Doses"]}
data={[stats.withOneDose, stats.withTwoDoses]}
/>
);
}
vaccines is an array and not a function. You are trying to run a map on vaccines. Try refactoring your code to this:
vaccines &&
vaccines.map((v, index) => {
// ...
})
Also do check: How to call an async function inside a UseEffect() in React?
here is the code, that works for you:
function DatafromFB() {
const[users, setUsers] = useState({});
useEffect(()=>{
const fetchVaccine = async () => {
try {
const docs = await db.collection("vaccines").get();;
docs.forEach((doc) => {
doc.data().vaccineDetails
.forEach(vaccineData=>{
fetchUsers(vaccineData.vaccine)
})
})
} catch (error) {
console.log("error", error);
}
}
const fetchUsers = async (vaccine)=>{
try {
const docs = await db.collection("users")
.where("doses.selectedVaccine", "==", vaccine).get();
docs.forEach(doc=>{
console.log(doc.data())
setUsers(doc.data());
})
}catch(error){
console.log("error", error);
}
}
fetchVaccine();
},[])
return (
<div>
<h1>{users?.doses?.selectedVaccine}</h1>
</div>
)
}
export default DatafromFB
what is ${index.vaccine} I think it must be v.vaccine
also setSize(snap.size); will set set size commonly not vaccine specific
I am trying to run a transaction which requires to get the data from a query:
firestore
.runTransaction((transaction) => {
const query = firestore
.collection("Lottories")
.doc("R3DYubrqFbbVfQNjYXfh")
.collection("sets")
.where("isAvailable", "==", false)
.limit(1);
return transaction.get(query).then((snapshot) => {
const ticketDoc = snapshot.docs[0];
const ticketDocData = ticketDoc.data();
const lottoUpdate = firestore
.collection("Lottories")
.doc("R3DYubrqFbbVfQNjYXfh")
.collection("sets")
.doc(ticketDoc.id);
const ticketUpdate = firestore
.collection("UserLotto")
.doc(userId)
.collection("tickets")
.doc("abc");
const countUpdate = firestore
.collection("UserData")
.doc(userId);
transaction.update(lottoUpdate, { isAvailable: true });
transaction.update(countUpdate, {
ticketCount: ticketCount - 2,
});
transaction.set(ticketUpdate, {
ticketId: ticketDoc.id,
lottoId: "abc",
claimed: false,
});
return ticketDocData;
});
})
.then((ticketDocData) => {
console.log(
"Transaction successfully committed!",
ticketDocData
);
setPopScreen("ticketPurchased");
})
.catch((error) => {
console.log("Transaction failed:", error);
});
For my application I need to run a query in order to complete my transaction. I Get the error:
Transaction failed: [FirebaseError: Function Transaction.get() requires its first argument to be a DocumentReference, but it was: a custom t object]
I understand transaction requires a document reference. Is there a work around this?
The nearest equivalent is to do the query with a higher limit, then in the transaction, get the doc again and check again for the required input condition....
// this will do the OP sets/updates, but *doesn't* assume the input
// doc meets the required condition (isAvailable==true)
// return a bool indicating success
function reserveDoc(lottoDoc) {
return firestore.runTransaction(transaction => {
return transaction.get(lottoDoc.ref).then(ticketDoc => {
// important, check the original condition again here
if (ticketDoc.data().isAvailable) {
// OP code to set/update goes here
return true
} else {
return false
}
})
})
}
// try a transaction on the first doc in the array. return if successful
// otherwise, try recursively on the remainder of the array
// return a bool indicating success
function reserveOneOf(lottoDocs) {
if (lottoDocs.length === 0) return false
return reserveDoc(lottoDocs[0]).then(success => {
// did it work? if not, try another doc
return success ? success : reserveOneOf(lottoDocs.slice(1))
})
}
function originalOPFunction() {
const query = firestore
.collection("Lottories")
.doc("R3DYubrqFbbVfQNjYXfh")
.collection("sets")
.where("isAvailable", "==", true) // note, I assume the OP query had a typo, checking for false
.limit(10);
return query.get().then(snapshot => {
return reserveOneOf(snapshot.docs)
}).then(success => {
// if !success here, the app must deal with NO docs currently meeting the criterion
// the OP needed to handle this circumstance anyway (if the limit(1) query returned no docs
})
}
The first param of Transaction get really is a document reference, not a query. This is confusing because documentReference.get() and transaction.get(documentReference) and `query.get(), kind of look and sound the same, but transaction is only atomic on a single doc, not on a set from a query, even one limited to 1.
transaction.get(query) the query must be a DocumentReference. So you need something like this:
db.collection("Lottories/R3DYubrqFbbVfQNjYXfh/sets")
.where("isAvailable", "==", false)
.limit(1)
.get()
.then((docs) => {
db.runTransaction((transaction) => transaction.get(docs[0]).then((doc) => {
if (doc.exists) //do something
}));
});
I'm trying to integrate stripe payment with my firestore firebase database. I'm having trouble figuring out add payment source function given in the firebase doc example. What am I missing here?
exports.addPaymentSource = functions.firestore
.document('Customers/{userId}/paymentSources/{paymentId}')
.onWrite((change, context) => {
let newPaymentSource = change.after.data();
if (newPaymentSource === null){
return null;
}
return admin.firestore().collection("Customers").doc(`${context.params.userId}`).get('customer_id')
.then((snapshot) => {
return snapshot.val();
}).then((customer) => {
return stripe.customers.createSource(customer, {newPaymentSource});
}).then((response) => {
return change.after.ref.parent.set(response);
}, (error) => {
return change.after.ref.parent.child('error').set(userFacingMessage(error));
}).then(() => {
return reportError(error, {user: context.params.userId});
});
});
I tried
console.log(snapshot.val())
and it gives me a type error.
Firestore database Image
Error Log Image
You're reading from Cloud Firestore, yet are using variable names and method calls that are for the Realtime Database. While both databases are part of Firebase, they're completely separate, and have different APIs.
The equivalent code for Firestore would be:
return admin.firestore().collection("Customers").doc(`${context.params.userId}`).get()
.then((doc) => {
return doc.data();
}).then((customer) => {
...
Also see:
the documentation on reading a document
I am creating a Stripe payment system, and am having difficulty making this integrated code functional. The code was pulled from here. What I am trying to do is create a database reference to the specific user ID (uid) of the user, since the createStripeCharge waits for a write event to occur to something like /stripe_customers/XCXaweADowefj/charges/QC123XYZ. I'm not sure, but perhaps my issue is that I am incorrectly referencing the customer. If you have any ideas or feedback about how I can make this function correctly I greatly appreciate it!
The Trigger (this causes the Cloud Function to work):
payByStripe(amount,email,userId, token): firebase.database.Reference {
return firebase.database().ref(`/stripe_customers/${userId}/charges/`).push({
amount:amount,
email:email,
token:token
});
}
Cloud Function:
exports.createStripeCharge = functions.database.ref('/stripe_customers/{userId}/charges/{id}').onWrite(event => {
const val = event.data.val();
if (val === null || val.id || val.error) return null;
return admin.database().ref(`/stripe_customers/${event.params.userId}/customer_id`).once('value').then(snapshot => {
return snapshot.val();
}).then(customer => {
const amount = val.amount;
const idempotency_key = event.params.id;
let charge = {amount, currency, customer};
if (val.source !== null) charge.source = val.source;
return stripe.charges.create(charge, {idempotency_key});
}).then(response => {
return event.data.adminRef.set(response);
}, error => {
return event.data.adminRef.child('error').set(userFacingMessage(error)).then(() => {
return reportError(error, {user: event.params.userId});
});
}
);
});
Currently, the database is creating the stripe customers, but the charge doesn't go through, with error message "You have passed a blank string for 'customer'. You should remove the 'customer' parameter from your request or supply a non-blank value."
Update is I've been iterating on this. Tried the following:
firebase.database().ref(`/stripe_customers/${userId}/charges/`).push({
amount:amount,
email:email,
token:token,
customer: userId
});
&&
firebase.database().ref(`/stripe_customers/${userId}/charges/`).push({
amount:amount,
email:email,
token:token,
customer_id:{
customer: userId
}
});
And still getting "You have passed a blank string for 'customer'. You should remove the 'customer' parameter from your request or supply a non-blank value."
I am trying to write a function in Cloud Functions that triggers every time a user gets created and which then saves that user into a list of users and finally increments a user counter.
However I am not sure if I am using promises correctly.
exports.saveUser = functions.auth.user().onCreate(event => {
const userId = event.data.uid
const saveUserToListPromise = db.collection("users").doc(userId).set({
"userId" : userId
})
var userCounterRef = db.collection("users").doc("userCounter");
const transactionPromise = db.runTransaction(t => {
return t.get(userCounterRef)
.then(doc => {
// Add one user to the userCounter
var newUserCounter = doc.data().userCounter + 1;
t.update(userCounterRef, { userCounter: newUserCounter });
});
})
.then(result => {
console.log('Transaction success!');
})
.catch(err => {
console.log('Transaction failure:', err);
});
return Promise.all([saveUserToListPromise, transactionPromise])
})
I want to make sure that even if many users register at once that my userCounter is still correct and that the saveUser function won't be terminated before the transaction and the save to the list has happened.
So I tried this out and it works just fine however I don't know if this is the correct way of achieving the functionality that I want and I also don't know if this still works when there are actually many users triggering that function at once.
Hope you can help me.
Thanks in advance.
The correct way to perform multiple writes atomically in a transaction is to perform all the writes with the Transaction object (t here) inside the transaction block. This ensures at all of the writes succeed, or none.
exports.saveUser = functions.auth.user().onCreate(event => {
const userId = event.data.uid
return db.runTransaction(t => {
const userCounterRef = db.collection("users").doc("userCounter")
return t.get(userCounterRef).then(doc => {
// Add one user to the userCounter
t.update(userCounterRef, { userCounter: FirebaseFirestore.FieldValue.increment(1) })
// And update the user's own doc
const userDoc = db.collection("users").doc(userId)
t.set(userDoc, { "userId" : userId })
})
})
.then(result => {
console.info('Transaction success!')
})
.catch(err => {
console.error('Transaction failure:', err)
})
})