How to Use React App as Widget

By adding script into host app

<script src="http://localhost:5000/static/js/user-table.main.bundle.js"></script>  

Host app will control where and when React UI will get displayed

<div id="user-table"></div>

<script type="text/javascript"> 
    EmailUserDetailTable.init({ 
    config: "configurationData", 
    selector:"user-table" 
    });  </script>