React Js Check First Letter of String is Uppercase

<!DOCTYPE html>
<html>

<body>
  <div id="app"></div>
  <script type="text/babel">
    const { useState } = React;
    function App() {
      const [input, setInput] = useState('Font aweosme icons');
      const isFirstLetterUppercase = input.length > 0 && input[0] === input[0].toUpperCase();

);
    }
    ReactDOM.render(<App />, document.getElementById("app"));
  </script>

.input-field {
      padding: 10px;
      border: 2px solid #007BFF;
      /* Blue border */
      border-radius: 5px;
      margin-bottom: 10px;
      font-size: 16px;
      width: 300px;
      outline: none;
    }

.check-button {
      background-color: #007BFF;
      /* Blue background */
      color: white;
      border: none;
      border-radius: 5px;
      padding: 10px 20px;
      cursor: pointer;
      font-size: 16px;
      transition: background-color 0.3s;
    }

.check-button:hover {
      background-color: #0056b3;
      /* Darker blue on hover */
    }
  </style>
</body>

</html>