Error: No Firebase App '[DEFAULT]' has been created - call Firebase App.initializeApp()

Question

I have a firebase database linked up to two apps, one being an iOS app and another being a web app coded in node.js which is a basic algorithm that sets data to the database

Answer 1

You are probably invoking firebase before the app is initialized. All calls to firebase. must come after .initializeApp();

firebase.initializeApp(config);
var db = firebase.firestore();