@swimmesberger/elarion-webpush

The browser half of Elarion Web Push: reach a user's browser or installed PWA while the app is closed. The server half is the Elarion.WebPush NuGet package (IWebPushSender, VAPID keys, the subscription store).

• pushAvailability() → 'available' | 'install-first' | 'unsupported'. install-first is iOS/iPadOS Safari outside a Home Screen app, where PushManager does not exist yet: show "Add to Home Screen first" instead of a switch that can never turn on.
• enablePush(api) — asks for permission inside the click handler (before any await, which Safari requires) and subscribes.
• subscribe, unsubscribe, isSubscribed, and refreshOnStart(api) — call the last one on every app start to heal subscriptions the push service rotated or the server cleaned up. They subscribe through the page's active service-worker registration (or the registration option) and wait at most registrationTimeoutMs (10 s) for a worker to activate, then throw a WebPushRegistrationError — navigator.serviceWorker.ready alone never settles when no worker is registered, for example on a dev server that does not serve one.
• @swimmesberger/elarion-webpush/sw — registerWebPushHandlers(self) for the service worker: shows the notification, focuses or opens the app at its URL on click, and re-subscribes on pushsubscriptionchange.

Page

import { enablePush, fetchWebPushApi, pushAvailability, refreshOnStart } from '@swimmesberger/elarion-webpush'

const api = fetchWebPushApi() // the endpoints app.MapElarionWebPush() maps under /webpush

await navigator.serviceWorker.register('/sw.js', { type: 'module' })
void refreshOnStart(api)

switch (pushAvailability()) {
  case 'available':
    button.onclick = async () => console.log(await enablePush(api)) // 'subscribed' | 'denied' | 'dismissed'
    break
  case 'install-first':
    hint.textContent = 'Add this app to your Home Screen to turn on notifications.'
    break
}

When the application exposes its own webPush.* handlers instead of MapElarionWebPush, adapt the generated JSON-RPC client:

const api: WebPushServerApi = {
  getPublicKey: async () => (await rpc.webPush.publicKey({})).publicKey,
  subscribe: async (subscription) => { await rpc.webPush.subscribe(subscription) },
  unsubscribe: async (endpoint) => { await rpc.webPush.unsubscribe({ endpoint }) },
}

Service worker

import { registerWebPushHandlers } from '@swimmesberger/elarion-webpush/sw'

registerWebPushHandlers(self, { icon: '/icons/192.png', badge: '/icons/badge.png' })

The module is ESM: bundle the worker (e.g. vite-plugin-pwa injectManifest) or register it with { type: 'module' }.