wop-toasty https://www.npmjs.com/package/wop-toasty

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
    <script async defer src="script.js"></script>
  <script async defer src="https://unpkg.com/wop-toasty@0.1.6/dist/woptoasty.js"></script>
  </head>
  <body>
    <button onclick="toasty.show()">Show Toasty!</button>
    <wop-toasty></wop-toasty>
  </body>

</html>

// Code goes here
let toasty;
window.onload = () => {
  toasty = document.querySelector('wop-toasty');
};
//const toasty = document.querySelector('wop-toasty');

/* Styles go here */