Unlock the Power of Progressive Web Apps

Enhance User Experience with Notifications, Caching, and Messages

When you visit a website, you’ve likely encountered prompts requesting permission to display notifications or noticed that some sites load faster on subsequent visits due to caching. These features are just a few examples of how building Progressive Web Apps (PWAs) can elevate the user experience.

Notifications: The Key to Seamless Engagement

Notifications have become ubiquitous, and for good reason. By enabling notifications, users can navigate to other browser tabs while waiting for an event to happen on a website, such as receiving a message in a chat.

To request access to notifications, create a file named notifications.js in the public/js folder and add it to your page.

Requesting Access and Triggering Notifications

To request access, use the Notification.requestPermission() method. Once permission is granted, you can trigger a notification using the registration.showNotification() method. This method offers various options for customizing the look and behavior of your notifications.

// Request permission
Notification.requestPermission().then(permission => {
  if (permission === 'granted') {
    // Trigger a notification
    registration.showNotification('Hello, world!');
  }
});

Caching: The Secret to Faster Load Times

Caching is essential for improving the user experience. By implementing a cache system, you can reduce the load on your server and provide faster access to resources.

We’ll demonstrate how to implement a cache system that fetches previous records, known as stale-while-revalidate. This approach is useful for information that rarely changes, such as a list of countries or a user avatar image.

// Implement a cache system
self.addEventListener('fetch', event => {
  event.respondWith(
    caches.open('my-cache').then(cache => {
      return cache.match(event.request).then(response => {
        if (response) {
          return response;
        } else {
          return fetch(event.request);
        }
      });
    })
  );
});

The Message Event: Bridging the Gap between Service Worker and Client

The message event allows for communication between the service worker and the client. This is useful for calling service worker methods like skipWaiting.

To communicate from the client to the service worker, post a message from the client side and receive it with the message event on the service worker side.

// Post a message from the client side
navigator.serviceWorker.controller.postMessage('Hello, service worker!');

// Receive the message on the service worker side
self.addEventListener('message', event => {
  console.log(event.data); // Output: "Hello, service worker!"
});

Compatibility and Best Practices

When implementing PWAs, it’s essential to ensure compatibility with various browsers and devices. Always check tools like MDN and Can I Use to ensure support for the features you’re using.

Additionally, be mindful of caching implementation to avoid filling the user’s browser cache.