used in pushManager.Subscribe to correctly encode the key to a Uint8Array

urlBase64ToUint8Array.js

function urlBase64ToUint8Array(base64String) {
  const padding = '='.repeat((4 - base64String.length % 4) % 4);
  const base64 = (base64String + padding)
    .replace(/\-/g, '+')
    .replace(/_/g, '/')
  ;
  const rawData = window.atob(base64);
  return Uint8Array.from([...rawData].map((char) => char.charCodeAt(0)));
}