Adding Auth

gistfile1.txt

var user = null;
        
var provider = new firebase.auth.GoogleAuthProvider();
firebase.auth().useDeviceLanguage();

firebase.auth().signInWithPopup(provider).then(function(result) {
    user = result.user;

    // All the Firestore code with 'enablePersistence()' goes here

}).catch(function(error) {
    console.error(error.message);
});