title: TypeScript and React issue
body: <p>Well, recently I've started using the React.js library, and now I'm trying to use it with Firebase Hosting, with the TypeScript language. But, every time I try to write some code using tsx it just doesn't work, for example:</p>
  
  <pre><code>import * as React from "react"; //red underline under "react"
  import "./App.css";
  
  import logo from "./logo.svg";
  
  class App extends React.Component {
    render() {
      return &lt;h1&gt;Hello&lt;/h1&gt;; //red underline under &lt;h1&gt; and &lt;/h1&gt;
    }
  }
  
  export default App;
  </code></pre>
  
  <p>that way I just can't write any jsx code here, because it always appears the issue:</p>
  
  <pre><code>test.tsx(1,1): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists
  </code></pre>
  
  <p>Can somebody please help me with this?</p>