Added comments & cleaned up a bit.

Author: digitalnomad91

src/lib/notifications.ts

@@ -1,69 +1,37 @@
+/**
+ * Imports for web push, Firebase messaging, Prisma ORM, and type definitions.
+ */
 import webpush, { WebPushError } from 'web-push'
 import { messaging } from './firebase' // Adjust as needed
-import { PrismaClient, Subscription } from '@prisma/client'
+import { Subscription } from '@prisma/client'
 import { JsonValue } from '@prisma/client/runtime/library'
+import prisma from '@/lib/db'
 
-const prisma = new PrismaClient()
-
-// Interfaces extending the Prisma Subscription type
-export interface WebSubscription extends Subscription {
-  type: 'web'
-  keys: JsonValue // Represents { auth: string; p256dh: string } as JsonValue
-}
-
-// Interface extending the Prisma Subscription type
-export interface FcmSubscription extends Subscription {
-  type: 'fcm'
-  keys: JsonValue // Represents { token: string } as JsonValue
-}
-
-// Union type covering both subscription types
-export type SubscriptionRecord = WebSubscription | FcmSubscription
-
-// Notification payload interface
-interface NotificationPayload {
-  title: string
-  body: string
-  url: string
-  icon?: string
-  badge?: string
-}
-
-// Helper function to validate web keys
-export function isWebKeys(keys: JsonValue): keys is { auth: string; p256dh: string } {
-  return (
-    typeof keys === 'object' &&
-    keys !== null &&
-    'auth' in keys &&
-    'p256dh' in keys &&
-    typeof (keys as any).auth === 'string' &&
-    typeof (keys as any).p256dh === 'string'
-  )
-}
-
-// Helper function to validate FCM keys
-export function isFcmKeys(keys: JsonValue): keys is { token: string } {
-  return (
-    typeof keys === 'object' &&
-    keys !== null &&
-    'token' in keys &&
-    typeof (keys as any).token === 'string'
-  )
-}
-
-// Unified function to send notifications
+/**
+ * Sends a push notification to a subscription using either web push (VAPID) or FCM.
+ *
+ * @param subscription - The subscription record, which can be either WebSubscription or FcmSubscription.
+ * @param notificationPayload - The notification payload containing title, body, url, etc.
+ *
+ * If the subscription type is 'web', it will send a web push notification.
+ * If the subscription type is 'fcm', it will send an FCM notification.
+ * If the subscription is invalid (e.g., expired or unregistered), it will be removed from the database.
+ */
 export async function sendNotification(
   subscription: SubscriptionRecord,
   notificationPayload: NotificationPayload
 ): Promise<void> {
   try {
     console.log('Sending notification to subscription:', subscription)
 
+    // Handle browser-based web push notifications.
     if (subscription.type === 'web') {
+      // Validate that the subscription keys match the structure required by web push.
       if (!isWebKeys(subscription.keys)) {
         throw new Error(`Invalid keys for web subscription: ${JSON.stringify(subscription.keys)}`)
       }
 
+      // Construct and send a web push notification.
       await webpush.sendNotification(
         {
           endpoint: subscription.endpoint,
@@ -80,11 +48,15 @@ export async function sendNotification(
           url: notificationPayload.url,
         })
       )
-    } else if (subscription.type === 'fcm') {
+    }
+    // Handle mobile push notifications using Firebase Cloud Messaging.
+    else if (subscription.type === 'fcm') {
+      // Validate that the subscription keys match the structure required by FCM.
       if (!isFcmKeys(subscription.keys)) {
         throw new Error(`Invalid keys for FCM subscription: ${JSON.stringify(subscription.keys)}`)
       }
 
+      // Construct the FCM message.
       const fcmMessage = {
         notification: {
           title: notificationPayload.title,
@@ -96,11 +68,17 @@ export async function sendNotification(
         token: subscription.keys.token,
       }
 
+      // Send the FCM message using Firebase.
       const response = await messaging.send(fcmMessage)
       console.log('FCM response:', response)
     }
   } catch (error) {
+    /**
+     * Handle errors appropriately. Depending on the type of subscription,
+     * remove invalid or expired subscriptions from the database if necessary.
+     */
     if (subscription.type === 'web' && error instanceof WebPushError) {
+      // Status code 410 indicates that the subscription is no longer valid.
       if (error.statusCode === 410) {
         await prisma.subscription.delete({ where: { id: subscription.id } })
         console.log(`Subscription with id ${subscription.id} removed due to expiration.`)
@@ -109,25 +87,96 @@ export async function sendNotification(
           `Failed to send notification to subscription id ${subscription.id}:`,
           error.statusCode,
           error.body
-        ) //error()
+        )
       }
     } else if (subscription.type === 'fcm') {
-      // Handle FCM-specific errors
+      // These error codes indicate an invalid or unregistered FCM token.
       if (
         error.code === 'messaging/invalid-registration-token' ||
         error.code === 'messaging/registration-token-not-registered'
       ) {
-        // Remove the invalid token from the database
         await prisma.subscription.delete({ where: { id: subscription.id } })
         console.log(`Removed invalid FCM token for subscription id ${subscription.id}.`)
       } else {
-        console.log(`Failed to send FCM notification to subscription id ${subscription.id}:`, error) //error()
+        console.log(`Failed to send FCM notification to subscription id ${subscription.id}:`, error)
       }
     } else {
       console.log(
         `An error occurred while sending notification to subscription id ${subscription.id}:`,
         error
-      ) //error()
+      )
     }
   }
 }
+
+/**
+ * An interface that extends the Prisma Subscription model for 'web' subscriptions.
+ * This includes the additional `type` and `keys` fields relevant to web push subscriptions.
+ */
+export interface WebSubscription extends Subscription {
+  type: 'web'
+  // The keys stored as JsonValue actually correspond to { auth: string; p256dh: string }
+  keys: JsonValue
+}
+
+/**
+ * An interface that extends the Prisma Subscription model for 'fcm' subscriptions.
+ * This includes the additional `type` and `keys` fields relevant to Firebase Cloud Messaging subscriptions.
+ */
+export interface FcmSubscription extends Subscription {
+  type: 'fcm'
+  // The keys stored as JsonValue actually correspond to { token: string }
+  keys: JsonValue
+}
+
+/**
+ * A union type that represents either a WebSubscription or an FcmSubscription.
+ * Used for handling either type of push subscription in a unified way.
+ */
+export type SubscriptionRecord = WebSubscription | FcmSubscription
+
+/**
+ * The payload for the notification, including title, body, url, icon, and badge.
+ * Used for constructing messages for both web push and FCM.
+ */
+interface NotificationPayload {
+  title: string
+  body: string
+  url: string
+  icon?: string
+  badge?: string
+}
+
+/**
+ * Type guard to check if the given JsonValue matches
+ * the structure required by a web push subscription ({ auth, p256dh }).
+ *
+ * @param keys The JsonValue that should contain web push keys.
+ * @returns True if the object has valid auth and p256dh strings; otherwise, false.
+ */
+export function isWebKeys(keys: JsonValue): keys is { auth: string; p256dh: string } {
+  return (
+    typeof keys === 'object' &&
+    keys !== null &&
+    'auth' in keys &&
+    'p256dh' in keys &&
+    typeof (keys as any).auth === 'string' &&
+    typeof (keys as any).p256dh === 'string'
+  )
+}
+
+/**
+ * Type guard to check if the given JsonValue matches
+ * the structure required by an FCM subscription ({ token }).
+ *
+ * @param keys The JsonValue that should contain the FCM token.
+ * @returns True if the object has a valid token string; otherwise, false.
+ */
+export function isFcmKeys(keys: JsonValue): keys is { token: string } {
+  return (
+    typeof keys === 'object' &&
+    keys !== null &&
+    'token' in keys &&
+    typeof (keys as any).token === 'string'
+  )
+}