refactor: change App component to TSX

and apply `AppProps` interface

Author: DoubleU23

src/App.jsx

@@ -0,0 +1,21 @@
+import React, { PureComponent } from 'react'
+
+import JsTestComponent from 'components/JsTestComponent/JsTestComponent.jsx'
+import TsTestComponent from 'components/TsTestComponent/TsTestComponent'
+
+interface AppProps {
+ param1?: string
+}
+
+class App extends PureComponent {
+  render(props: AppProps): string {
+    return (
+      <>
+        <h1 id="app_headline">@stackr23/webpack up and running!</h1>
+        <JsTestComponent /* testParam="teststring" */ />
+      </>
+    )
+  }
+}
+export default App
+

src/App.tsx

@@ -2,7 +2,7 @@
 import React from 'react'
 import ReactDOM from 'react-dom'
 
-import App from './App.jsx'
+import App from './App'
 
 
 const rootElement = document.getElementById('app-root') || document.getElementById('app')