Change to typescript template

src/App.test.tsx

@@ -1,3 +1,4 @@
+import React from 'react';
 import { render, screen } from '@testing-library/react';
 import App from './App';
 

src/App.tsx

@@ -1,3 +1,4 @@
+import React from 'react';
 import logo from './logo.svg';
 import './App.css';
 
@@ -7,7 +8,7 @@ function App() {
       <header className="App-header">
         <img src={logo} className="App-logo" alt="logo" />
         <p>
-          Edit <code>src/App.js</code> and save to reload.
+          Edit <code>src/App.tsx</code> and save to reload.
         </p>
         <a
           className="App-link"

src/index.tsx

@@ -4,7 +4,9 @@ import './index.css';
 import App from './App';
 import reportWebVitals from './reportWebVitals';
 
-const root = ReactDOM.createRoot(document.getElementById('root'));
+const root = ReactDOM.createRoot(
+  document.getElementById('root') as HTMLElement
+);
 root.render(
   <React.StrictMode>
     <App />

src/react-app-env.d.ts

@@ -0,0 +1 @@
+/// <reference types="react-scripts" />

src/reportWebVitals.ts

@@ -1,4 +1,6 @@
-const reportWebVitals = onPerfEntry => {
+import { ReportHandler } from 'web-vitals';
+
+const reportWebVitals = (onPerfEntry?: ReportHandler) => {
   if (onPerfEntry && onPerfEntry instanceof Function) {
     import('web-vitals').then(({ getCLS, getFID, getFCP, getLCP, getTTFB }) => {
       getCLS(onPerfEntry);