Push Notifications for Installable Apps

1. Introduction

Push notifications are a powerful feature of Progressive Web Apps (PWAs) that allow you to send timely updates to users, even when they are not actively using the app. This lesson explores the mechanism of push notifications, their implementation, and best practices for effective usage.

2. Key Concepts

3. Implementation

3.1 Step-by-Step Process

1. Register the Service Worker.
2. Request Permission for Notifications.
3. Subscribe the User for Push Notifications.
4. Send a Push Notification from the Server.
5. Handle the Push Notification in the Service Worker.

3.2 Example Code

if ('serviceWorker' in navigator) {
    navigator.serviceWorker.register('/sw.js')
    .then(function(registration) {
        console.log('Service Worker registered with scope:', registration.scope);
    });
}

Notification.requestPermission().then(function(permission) {
    if (permission === 'granted') {
        console.log('Notification permission granted.');
    }
});

self.addEventListener('push', function(event) {
    const options = {
        body: event.data ? event.data.text() : 'No payload',
        icon: 'images/icon.png',
        badge: 'images/badge.png'
    };
    event.waitUntil(
        self.registration.showNotification('Push Notification', options)
    );
});

4. Best Practices

• Always ask for user permission before sending notifications.
• Personalize notifications to enhance user engagement.
• Limit the frequency of notifications to avoid overwhelming users.
• Provide an option for users to manage their subscription preferences.
• Test notifications thoroughly to ensure they display correctly on all devices.

5. FAQ