app.js

(function() {
  // Initialize Firebase
  const config = {
    apiKey: "AIzaSyBohS0b1b9oMqnXjcPbScGUQuVuPSTrFRg",
    authDomain: "graffite-c9805.firebaseapp.com",
    databaseURL: "https://graffite-c9805.firebaseio.com",
    projectId: "graffite-c9805",
    storageBucket: "graffite-c9805.appspot.com",
    messagingSenderId: "66234725427"
  };
  firebase.initializeApp(config);

  // Get elements
  const txtEmail = document.getElementById('txtEmail');
  const txtPassword = document.getElementById('txtPassword');
  const btnLogin = document.getElementById('btnLogin');
  const btnSignUp = document.getElementById('btnSignUp');
  const btnLogOut = document.getElementById('btnLogout');


 // Add login event
  btnLogin.addEventListener('click', e => {

      // Get email and pass
      const email = txtEmail.value;
      const pass = txtPassword.value;
      const auth = firebase.auth();


      // Sign in
      const promise = auth.signInWithEmailAndPassword(email, pass);
      promise.catch(e => console.log(e.message));

 });

    btnSignUp.addEventListener('click', e => {
      // Get email and pass
      // TODO: CHECK IF E-MAIL EXISTS
      const email = txtEmail.value;
      const pass = txtPassword.value;
      const auth = firebase.auth();

      // Sign in
      const promise = auth.createUserWithEmailAndPassword(email, pass);
      promise
        .catch(e => console.log(e.message));
      window.location.replace("app.html");
    });

    btnLogout.addEventListener('click', e => {
        firebase.auth().signOut();

      // Add a realtime Listener
      firebase.auth().onAuthStateChanged(firebaseUser => { if(firebaseUser) {
          console.log(firebaseUser);
          btnLogout.classList.remove('hide');

      } else {
          console.log('not logged in');
          btnLogout.classList.add('hide');
      }
            });
        });



}());