JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE HTML>
<html>
   <head>
   	<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
      <title>Authentication</title> 

      <script src="https://www.gstatic.com/firebasejs/4.12.1/firebase.js"></script>
   </head>
   <body id="index">  
      <input type="button" id="login" value="Login">
      <input type="button" id="create" value="Criar: [email protected]">
      <input type="button" id="update" value="Alterar senha">
      <input type="button" id="delete" value="Excluir: [email protected]">
      <input type="button" id="logout" value="Logout">
      
      <hr />
      <div id="console">
      
      </div>
   </body>

</html>

JavaScript

var config = {
  apiKey: "AIzaSyCDbKd0lhysddQAIQx9_ooye2TvXyLQn0Q",
  authDomain: "test-d7e7f.firebaseapp.com",
  databaseURL: "https://test-d7e7f.firebaseio.com",
  projectId: "test-d7e7f",
  storageBucket: "test-d7e7f.appspot.com",
  messagingSenderId: "466448961658"
};
firebase.initializeApp(config);

//escutando status do firebase
firebase.auth().onAuthStateChanged(function(user) {
  if (user) {
    //online
    document.getElementById("console").innerHTML = JSON.stringify( user );
  } else {
    document.getElementById("console").innerHTML = 'OffLine!';
  }
});


//Ação de Login do botão #login
document.getElementById("login").onclick = function() { 


	firebase.auth().signInWithEmailAndPassword('[email protected]', '123mudar').catch(function(error) { 
  
  document.getElementById("console").innerHTML = JSON.stringify( error );
  
  });
};


//Ação de Login do botão #logout
document.getElementById("logout").onclick = function() { 

  firebase.auth().signOut()
  .then(function() {
    document.getElementById("console").innerHTML = 'Logout';
  }, function(error) {
    document.getElementById("console").innerHTML = JSON.stringify( error );
  });

};

//Ação de alterar senha do botão #update
document.getElementById("update").onclick = function() { 

firebase.auth().currentUser.updatePassword('123mudar')
.then(function() {
	document.getElementById("console").innerHTML = 'Senha Alterada!';
})
.catch(function(error) {
	document.getElementById("console").innerHTML = JSON.stringify( error );
}); 


};

//Ação de criar do botão #create
document.getElementById("create").onclick = function() { 


firebase.auth().createUserWithEmailAndPassword('[email protected]', "123mudar").catch(function(error) {
  document.getElementById("console").innerHTML = JSON.stringify( error );
});

 
};

//Ação de excluir do botão #delete
document.getElementById("delete").onclick = function() { 


var user = firebase.auth().currentUser;
user.delete().then(function() {
  // User...