• Create a new wiki page and add this in its content (see also https://reactjs.org/docs/add-react-to-a-website.html):
  {{html}}
  <div id="like_button_container"></div>
  {{/html}}
• Edit the page with the object editor and add a JavaScriptExtension object with this content:
  require.config({
   paths: {
     'react': 'https://unpkg.com/react@16/umd/react.production.min',
     'react-dom': 'https://unpkg.com/react-dom@16/umd/react-dom.production.min'
   }
  })
  
  define('likeButton', ['react'], function(React) {
   'use strict';
  
   class LikeButton extends React.Component {
      constructor(props) {
       super(props);
        this.state = { liked: false };
      }
  
      render() {
       if (this.state.liked) {
         return 'You liked this.';
        }
  
       return React.createElement(
         'button',
          { onClick: () => this.setState({ liked: true }) },
         'Like'
        );
      }
    }
  
   return LikeButton;
  });
  
  require(['react', 'react-dom', 'likeButton'], function(React, ReactDOM, LikeButton) {
   const domContainer = document.querySelector('#like_button_container');
    ReactDOM.render(React.createElement(LikeButton), domContainer);
  });
• Set the JSX object to be loaded "On this page or on demand". That's it!

Result