feat(workbox): make plugin fully asynchronous

docs/modules/workbox.md

@@ -20,9 +20,18 @@ workbox: {
 
 ## Workbox Window
 
-A global `$workbox` service is injected to the application, which can be used either by plugins (via `context.app.$workbox`) or pages (via `this.$workbox`).
+This module uses [workbox-window](https://developers.google.com/web/tools/workbox/modules/workbox-window) to register and communicate with workbox service worker.
+See docs for more information about use cases.
 
-See [workbox-window](https://developers.google.com/web/tools/workbox/modules/workbox-window) docs for more information about use cases.
+As service worker is registered in background, to access instance you have to await on a promise:
+
+```js
+const workbox = await window.$workbox
+
+if (workbox) {
+  // Service worker is available
+}
+```
 
 ## Options
 

packages/workbox/templates/sw.register.js

@@ -1,27 +1,18 @@
-function onError(error) {<% if (options.dev) { %>console.error('Error registering workbox:', error) <% } %>}
-
-export default function (ctx, inject) {
-  let workbox = {}
+async function register() {
+  if (!'serviceWorker' in navigator) {
+    throw new Error('serviceWorker is not supported in current browser!')
+  }
 
-  try {
-    // workbox-window does not detects unsupported browsers
-    if (!'serviceWorker' in navigator) {
-      throw new Error('serviceWorker is not supported in current browser!')
-    }
+  const { Workbox } = await import('workbox-cdn/workbox/workbox-window.<%= options.dev ? 'dev' : 'prod' %>.es5.mjs')
 
-    // Use require() instead of import() to prevent creating extra chunk
-    // Use es5 version to prevent crashing older browsers while parsing bundle
-    const { Workbox } = require('workbox-cdn/workbox/workbox-window.<%= options.dev ? 'dev' : 'prod' %>.es5.mjs')
+  const workbox = new Workbox('<%= options.swURL %>', {
+    scope: '<%= options.swScope %>'
+  })
 
-    workbox = new Workbox('<%= options.swURL %>', {
-      scope: '<%= options.swScope %>'
-    })
+  await workbox.register()
 
-    workbox.register().catch(onError)
-  } catch (error) {
-    onError(error)
-  }
-
-  // Inject as $workbox
-  inject('workbox', workbox)
+  return workbox
 }
+
+window.$workbox = register()
+  .catch(error => {<% if (options.dev) { %> console.error('Error registering workbox:', error) <% } %>})