07-prop-types.html

<body>
  <div id="root"></div>
  <script src="https://unpkg.com/react@16.12.0/umd/react.production.min.js"></script>
  <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.production.min.js"></script>
  <script src="https://unpkg.com/@babel/standalone@7.8.3/babel.js"></script>
  <script src="https://unpkg.com/prop-types@15.6.1/prop-types.js"></script>
  <script type="text/babel">
    const rootElement = document.getElementById('root')

    function SayHello({firstName, lastName}) {
      return (
        <div>
          Hello {firstName} {lastName}!
        </div>
      )
    }
    SayHello.propTypes = {
      firstName: PropTypes.string.isRequired,
      lastName: PropTypes.string.isRequired,
    }

    const element = <SayHello firstName={false} />

    ReactDOM.render(element, rootElement)
  </script>
</body>