DB.collection is not a function in firebase?

Question

I am trying to connect to firebase realtime database (not firestore) but I get the error that db.collection is not a function. Other answers in StackOverflow are mentioned with respect to Firestore. Thanks for your help.

const admin = require('firebase-admin');

// Firebase configuration - this should not be public.
// Please use your own config if you intend to use this code.
var firebaseConfig = {
  apiKey: "xxxxxxxxxxxxxxxxxx",
  authDomain: "xxxxxxxxxxxxxxxxxx",
  databaseURL: "xxxxxxxxxxxxxxxxxx",
  projectId: "xxxxxxxxxxxxxxxxxx",
  storageBucket: "xxxxxxxxxxxxxxxxxx",
  messagingSenderId: "xxxxxxxxxxxxxxxxxx",
}

// Initialize Firebase
admin.initializeApp(firebaseConfig)

const db = admin.database();
console.log("Database setup");

(async () => {
  try {
    let query = db.collection('users');
    console.log("Doing database query now");
    await query.get().then(querySnapshot => {
      console.log(querySnapshot);
    });
  } catch (error) {
    console.log(error);
  }
})();

Answer 1

const db = admin.database() is an instance of Firebase realtime database and not Firestore. To get an instance of Firestore, use admin.firestore().

const admin = require('firebase-admin');

admin.initializeApp(/* service account */)

const db = admin.firestore();
console.log("Firestore setup");

Admin SDK uses a service account and not the same public credentials. You can refer to the documentation for detailed information. You can get a service account from project settings.

Do note that if you are using Cloud functions then you can leave initializeApp() empty.