How to use useCollection react-firebase hook with firebase v9 - reactjs

Question

I want to use react-firebase-hooks for firestore, but I cant seem to make it work properly, I have collection of users and it has subcollection of budgets. If user is logged in I want to show his budgets. My code:
The problem is mainly in useCollection hook, where I need to pass user.uid, but user is undefined in the beginning. How else should I do this?
const Homepage = () => {
const [user, loading, error] = useAuthState(auth);
const [showAddBudgetModal, setShowAddBudgetModal] = useState(false);
const [value, dataLoading, dataError] = useCollection(collection(db, `users/${user!.uid}/budgets`), {
snapshotListenOptions: { includeMetadataChanges: true },
});
const [showAddExpenseModal, setShowAddExpenseModal] = useState(false);
const [addExpenseModalBudgetId, setAddExpenseModalBudgetId] = useState('');
const openAddExpenseModal = (budgetId?: any) => {
setShowAddExpenseModal(true);
setAddExpenseModalBudgetId(budgetId);
};
if (loading) {
return (
<div>
<p>Initialising User...</p>
</div>
);
}
if (error) {
return (
<div>
<p>Error: {error.message}</p>
</div>
);
}
if (user) {
return (
<div>
<h1>Welcome {user.displayName}!</h1>
<button onClick={logOut}>Logout</button>
<div className="buttons">
<button onClick={() => setShowAddBudgetModal(true)}>Add budget</button>
</div>
<AddBudgetModal show={showAddBudgetModal} onClose={() => setShowAddBudgetModal(false)}></AddBudgetModal>
<div>
{dataError && <strong>Error: {JSON.stringify(error)}</strong>}
{dataLoading && <span>Collection: Loading...</span>}
{value && user && (
<div>
{value.docs.map((budget) => (
<BudgetCard
key={budget.id}
name={budget.name}
max={budget.max}
onAddExpenseClick={() => openAddExpenseModal(budget.id)}
onViewExpensesClick={() => openAddExpenseModal(budget.id)}
></BudgetCard>
))}
</div>
)}
</div>
</div>
);
}
};
export default Homepage;

Answer 1

There are 2 ways to solve this problem in my opinion
First one is to use optional chaining to check whether the user exist or not eg:
const [value, dataLoading, dataError] = useCollection(user && query(
collection(getFirestore(app), "users", user.uid, "budgets"), {
snapshotListenOptions: {
includeMetadataChanges: true
},
});
For more information about this there is a similar thread about this issue.
Second way is to use useEffect hook to implement the same like this:
useEffect(() => {
if (user) {
const [value, dataLoading, dataError] = useCollection(user && query(
collection(getFirestore(app), "users", user.uid, "budgets"), {
snapshotListenOptions: {
includeMetadataChanges: true
},
});
}
}, [user]);
In this way your user can only be rendered if and only if data related to the user is loaded already, but make sure in future to not set user in useEffect as it will create an infinite loop as useEffect has provided user in dependencies array.
For more about usEffect you can go through this documentations