Denied permission by Firebase

Question

I work with Firebase and for my Firestore Database I created the rules:

// Budgets
match /budgets/{budget} {
    allow read: if request.auth != null;
  allow update, delete, create: if request.auth != null && request.auth.uid == request.resource.data.userId;
}

Somehow Firebase allows me to create a budget. But unfortunately when I try to delete created budget I receive error:

FirebaseError: [code=permission-denied]: Missing or insufficient permissions.

Code for deleting a budget:

async function deleteBudget({ id }) {
    try {
        const budgetToDeleteQuery = query(collection(db, 'budgets'), where('id', '==', id), where('userId', '==', currentUser?.uid));
        const budgetToDeleteData = await getDocs(budgetToDeleteQuery);
        const budgetToDelete = doc(db, 'budgets', budgetToDeleteData.docs[0].id);
        await deleteDoc(budgetToDelete);
    } catch (error) {
        alert(error);
    }
    // setBudgets(prevState => prevState.filter(item => item.id !== id));
}

Can anyone tell me what's the problem here?

Answer 1

To delete, use resource because it is the document before the operation takes place, which in this case is the budget you want to delete.

Check the code below.

 // Budgets
 match /budgets/{budget} {
       allow read: if request.auth != null;
       allow update, create: if request.auth != null && request.auth.uid == request.resource.data.userId;
       allow delete: if request.auth.uid == resource.data.userId
    }