owncast/web/services/notifications-service.ts

export async function saveNotificationRegistration(channel, destination, accessToken) {
  const URL_REGISTER_NOTIFICATION = `/api/notifications/register`;

  const options = {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ channel, destination }),
  };

  try {
    await fetch(`${URL_REGISTER_NOTIFICATION}?accessToken=${accessToken}`, options);
  } catch (e) {
    console.error(e);
  }
}

export function isPushNotificationSupported() {
  return 'serviceWorker' in navigator && 'PushManager' in window;
}

function urlBase64ToUint8Array(base64String: string) {
  const padding = '='.repeat((4 - (base64String.length % 4)) % 4);
  const base64 = (base64String + padding).replace(/-/g, '+').replace(/_/g, '/');

  const rawData = window.atob(base64);
  const outputArray = new Uint8Array(rawData.length);

  for (let i = 0; i < rawData.length; ++i) {
    outputArray[i] = rawData.charCodeAt(i);
  }
  return outputArray;
}

export async function registerWebPushNotifications(vapidPublicKey) {
  const registration = await navigator.serviceWorker.ready;
  let subscription = await registration.pushManager.getSubscription();

  if (!subscription) {
    subscription = await registration.pushManager.subscribe({
      userVisibleOnly: true,
      applicationServerKey: urlBase64ToUint8Array(vapidPublicKey),
    });
  }

  return JSON.stringify(subscription);
}