const firebase = require("firebase");
function signInWithFacebook(firebaseAuth: firebase.auth.Auth) {
  firebaseAuth.signInWithPopup(new firebase.auth.FacebookAuthProvider());
}
 
function addTodo(text: string, todoCollection: firebase.firestore.CollectionReference) {
  return todoCollection.add({ text });
}
 
const MockApp = require("mockbase");
const app = new MockApp("app name");
signInWithFacebook(app.auth());
addTodo("Clean home up", app.firestore().collection("todo"));