web-push.md

@@ -12,7 +12,7 @@ controlling the web browser's source code. Here named PROVIDER. An example of a
 PROVIDER is FCM (Firebase Cloud Messaging) which is owned by Google.
 3) The Web Application that a user is visiting from their web browser. Let's
 call this the SERVICE (short for Web Push application service)
-[4) A Custom Web Push Intermediary Service, either third party or self-hosted.
+4) A Custom Web Push Intermediary Service, either third party or self-hosted.
 Called INTERMEDIARY here. FCM also may fit in this category if the SERVICE
 has an API key from FCM.]
 
@@ -105,7 +105,7 @@ Here's a version which can be used for testing locally.  Note there can be
 caching issues in your browser!  Incognito is highly recommended.
 
 sw-dev.ts
-
+```
 self.addEventListener('push', function(event: PushEvent) {
   console.log('Received a push message', event);
 
@@ -122,10 +122,11 @@ self.addEventListener('push', function(event: PushEvent) {
     })
   );
 });
+```
 
 
 vue.config.js
-
+```
 module.exports = {
   pwa: {
     workboxOptions: {
@@ -133,6 +134,7 @@ module.exports = {
     }
   }
 }
+```
 
 Once we have the service worker registered and the ServiceWorkerRegistration is
 returned, we then have access to a `pushManager` property object.  This property
@@ -152,13 +154,13 @@ being used by the BROWSER in decrypting the messages coming from the SERVICE.
 The VAPID (Voluntary Application Server Identification) key provides more
 security and authenticity for web push notifications in the following ways:
 
-    Identifying the Application Server:
+Identifying the Application Server:
     
         The VAPID key is used to identify the application server that is sending
 	the push notifications. This ensures that the push notifications are
 	authentic and not sent by a malicious third party.
 	
-    Encrypting the Messages:
+Encrypting the Messages:
     
         The VAPID key is used to sign the push notifications sent by the
 	application server, ensuring that they are not tampered with during
@@ -184,6 +186,7 @@ PROVIDER which creates and stores a special URL for that BROWSER.
 
 Here's a bit of code describing the above process:
 
+```
 // b64 is the VAPID
 b64 = 'BEl62iUYgUivxIkv69yViEuiBIa-Ib9-SkvMeAtA3LFgDzkrxZJjSgSnfckjBJuBkr3qBUYIHBQFLXYp5Nksh8U';
 const applicationServerKey = urlBase64ToUint8Array(b64);
@@ -199,6 +202,7 @@ registration.pushManager.subscribe(options)
   .catch(function(error) {
     console.error('Push subscription failed:', error);
   });
+```
 
 In this example, the `applicationServerKey` variable contains the VAPID public
 key, which is converted to a `Uint8Array` using a function such as this:
@@ -221,6 +225,16 @@ export function toUint8Array(base64String: string, atobFn: typeof atob): Uint8Ar
 The options object is of type `PushSubscriptionOptions`, which includes the
 `userVisibleOnly` and `applicationServerKey` (ie VAPID public key) properties.
 
+    options: An object that contains the options used for creating the
+    subscription. This object itself has the following sub-properties:
+    
+      applicationServerKey: A public key your push service uses for application
+      server identification. This is normally a Uint8Array.
+    
+      userVisibleOnly: A boolean value indicating that the push messages that
+      are sent should be made visible to the user through a notification.
+      This is often set to true.
+
 The subscribe() method returns a `Promise` that resolves to a `PushSubscription`
 object containing details of the subscription, such as the endpoint URL and the
 public key.  The returned data would have a form like this:
@@ -242,16 +256,6 @@ public key.  The returned data would have a form like this:
     representing the subscription's expiration time in milliseconds since
     01 January, 1970 UTC. This can be null if the subscription never expires.
 
-    options: An object that contains the options used for creating the
-    subscription. This object itself has the following sub-properties:
-    
-      applicationServerKey: A public key your push service uses for application
-      server identification. This is normally a Uint8Array.
-    
-      userVisibleOnly: A boolean value indicating that the push messages that
-      are sent should be made visible to the user through a notification.
-      This is often set to true.
-
 The BROWSER will, internally, then use that URL to check for incoming messages
 by way of the service worker we described earlier. The BROWSER also sends this
 URL back to SERVICE which will use that URL to send messages to the BROWSER via
@@ -266,6 +270,7 @@ via the PROVIDER so that they reach the BROWSER service worker.
 Just to remind us that in our service worker our code for receiving messages
 will look something like this:
 
+```
 self.addEventListener('push', function(event: PushEvent) {
   console.log('Received a push message', event);
 
@@ -282,7 +287,7 @@ self.addEventListener('push', function(event: PushEvent) {
     })
   );
 });
-
+```
 
 
 Now to address the issue of receiving notification messages on mobile devices.