Cannot find namespace 'FirebaseFirestore' - Node.js, Express, Typescript

Question

I'm using the Firebase Admin SDK in my Express + Typescript server. I'm trying to use Firestore's method withConverter() However, I get the error "Cannot find namespace 'FirebaseFirestore'.ts(2503)". How can I deal with this?

admin.initializeApp({
    credential: admin.credential.cert(serviceAccount)
});

const firestore = admin.firestore();

interface BlogpostColletion {
    text: String,
    title: String,
}

interface UsersCollection {
    blogposts: BlogpostColletion
}

const converter = {
    toFirestore: (data: UsersCollection) => data,
    // PROBLEM HERE👇 "Cannot find namespace 'FirebaseFirestore'.ts(2503)" 
    fromFirestore: (snap: FirebaseFirestore.QueryDocumentSnapshot) =>
        snap.data() as UsersCollection
}

Answer 1

You can import QueryDocumentSnapshot from Admin SDK like this:

import * as admin from "firebase-admin"

fromFirestore: (snap: admin.firestore.QueryDocumentSnapshot)