title: "Firebase is not a constructor" -- need to downgrade Firebase, how to do it?
body: <p>I am currently learning React.js from <a href="https://www.udemy.com/learn-and-understand-reactjs/learn/v4/overview" rel="nofollow">this course on Udemy</a>. I've reached Lecture 27 and I'm at a standstill. I keep getting the error "Firebase is not a constructor." Just from looking at other people's issues, I've figured out that I need to downgrade Firebase down to V. 2. The only question is, how do I go about doing this?</p>
  
  <p>I went to my app.jsx file and changed Firebase down to "^2.4.2". I also reloaded my entire app. I still get the same error, "Firebase is not a constructor".</p>
  
  <p>Can anyone give me any pointers here? I'd really like to get this app to work. What else do I need to change?</p>