var authProvider = new firebase.auth.GoogleAuthProvider();  여기서 GoogleAuthProvider()함수가 없다고 뜹니다.

<p>현재 강좌에서 빠진거같은데</p>
<pre class="language-markup"><code>&lt;script src="https://www.gstatic.com/firebasejs/5.9.1/firebase-auth.js"&gt;&lt;/script&gt;
&lt;script src="https://www.gstatic.com/firebasejs/5.9.1/firebase-database.js"&gt;&lt;/script&gt;
&lt;script src="https://www.gstatic.com/firebasejs/5.9.1/firebase-firestore.js"&gt;&lt;/script&gt;

맨위에 firebase-auth.js 모듈추가해줘야 auth()메소드 사용가능합니다.</code></pre>

인프런 커뮤니티 질문&답변

(anonymous function) Uncaught TypeError가 뜨네요 ㅠ