Firebase v9 on react JS

Question

I just want to check if i dont create an other chats on my firebase. I query all my chat with this email and then, i check if the array contain the email i wanna tchat with but it doesn't work. I'm using Firebase V9. Anyone has an idea ?

function Sidebar() { const [user] = useAuthState(auth);

const chatRef = collection(db, 'chats');
const qchatExist = query(chatRef, where('users', 'array-contains', user.email) );
const chatsSnapshot = getDocs(qchatExist);

const createChat = () => {

    const input = prompt('Please enter a email adresse');
    if(!input) return;
    if (EmailValidator.validate(input) && !chatAlreadyExists(input) && input !== user.email ) {
        console.log("valide");
        addDoc(collection(db, 'chats'),
        {
            users: [user.email, input],
        });
    }
    else {
        console.log('invalide');
    }
}

const chatAlreadyExists = (data) =>
    !!chatsSnapshot?.docs.find( 
        chat => 
            chat.data().users.find( (user) => user === data)?.length > 0
    );

code

Answer 1

you probably wanna use Collection Group Queries.

so you can query across all the chats collection at once.

https://firebase.google.com/docs/firestore/query-data/queries#:~:text=We%20can%20use,across%20all%20cities%3A

const users = query(collectionGroup(db, 'users'), where('email', '==', '[email protected]'));

and make sure you create indexes for the query.

Before using a collection group query, you must create an index that supports your collection group query. You can create an index through an error message, the console, or the Firebase CLI.