Unlock the Power of Progressive Web Apps
Imagine having a mobile app-like experience on the web, with features like offline functionality, fast loading times, and a seamless user interface. This is exactly what Progressive Web Apps (PWAs) offer. In this tutorial, we’ll dive into the world of PWAs and show you how to build one that meets all the Google Lighthouse checks.
Getting Started
Before we begin, let’s outline the requirements for this project. You’ll need:
- Node.js to run the server
- Express to run the HTTP server
- Nodemon to debug the server
- Chrome to check the website and debug your PWA
- OpenSSL to generate a self-signed certificate
Setting Up the Project
Create a basic HTTP server to generate your index.html file. In your package.json file, add the script “server-debug”: “nodemon –inspect server.js”. Then, create a public folder with an index.html file and a js folder containing a pwa.js file.
Building a PWA
To get Google to recognize your app as a fully functional PWA, you’ll need to meet certain criteria. Run the Lighthouse audit and you’ll see a list of red checks. Let’s tackle them one by one.
Adding a Manifest
Create a manifest file (pwa.webmanifest) and add it to your public folder. This will address the installability criterion and add a splash screen. Don’t forget to add a 512×512 image in your images folder, called splash-screen.png.
Optimizing Your PWA
Let’s optimize your PWA by adding a theme color, an icon for iOS devices, and a viewport to make sure the application is responsive. Update your index.html file accordingly.
Enabling HTTPS
To meet the HTTPS requirement, generate a self-signed certificate using OpenSSL. Then, update your server.js file to redirect to HTTPS.
Service Workers
A service worker is a piece of JavaScript code that handles the cache for assets and data. Create a service worker file (service-worker.js) and register it in your pwa.js file. Use the install event to specify the files you want to save in your cache.
Making it Work Offline
Update your fetch event to check every request made on the page. If there’s a match found in the cache, use the cached version. Create a status file (status.js) to change the page state from online to offline whenever the client loses connection.
Putting it All Together
Reload the page and view your files in the cache. If the connection is working, you should see the cached files. If you select the offline option, you should see the status change.
Compatibility and Pros and Cons
PWAs have varying compatibility across browsers, but service workers generally have good support. On the other hand, web app manifest is less compatible. Always check for polyfills and fallbacks for when the browser doesn’t have the technology implemented.
The pros of PWAs include fast loading times, ease of implementation, and independence from libraries. However, the first visit to a page can be slow, and add to home screen functionality is seldom used.
Is it Worth it?
Implementing PWA technology is worth it, especially for websites that require offline access to information. With PWAs, you can give your users a seamless experience, even when they’re offline.
What do you think of PWAs? Have you built anything with it? Share your thoughts and experiences in the comments below!