🛰️ AngularJS Service Workers & PWA – Turn AngularJS Apps into Offline-First Progressive Web Apps (2025 Guide)

🧲 Introduction – Why Add Service Workers & PWA Support to AngularJS?

In the era of mobile-first and offline-first web apps, Progressive Web Apps (PWAs) are a must-have. Although AngularJS predates PWA support and service workers, you can still implement these features manually or with helper libraries to add:

• Offline capabilities
• Background sync
• Improved performance and caching
• PWA install prompts and app-like behavior

🎯 In this guide, you’ll learn:

• What service workers and PWAs are
• How to register a service worker in AngularJS
• How to configure caching, offline support, and manifests
• Best practices for deploying a PWA-enabled AngularJS app

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🚀 What is a Service Worker?

A Service Worker is a background script that:

• Intercepts and handles network requests
• Caches files and API responses
• Works offline and syncs in the background
• Powers push notifications and background updates

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🧱 What is a PWA (Progressive Web App)?

A PWA combines the best of web and mobile apps. Features include:

• Responsive design
• Offline access
• Add-to-home-screen support
• Native-like performance
• HTTPS-only deployment

✅ AngularJS doesn’t support PWAs out-of-the-box but you can manually add these capabilities.

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⚙️ Step 1: Create a service-worker.js File

Place this file in your AngularJS project root (typically next to index.html).

const CACHE_NAME = 'angularjs-pwa-cache-v1';
const urlsToCache = [
  '/',
  '/index.html',
  '/styles.css',
  '/app.js',
  '/images/logo.png'
];

// Install SW and cache static assets
self.addEventListener('install', function(event) {
  event.waitUntil(
    caches.open(CACHE_NAME).then(function(cache) {
      return cache.addAll(urlsToCache);
    })
  );
});

// Serve from cache
self.addEventListener('fetch', function(event) {
  event.respondWith(
    caches.match(event.request).then(function(response) {
      return response || fetch(event.request);
    })
  );
});

✅ This caches your static files and serves them offline.

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⚙️ Step 2: Register the Service Worker in AngularJS

Add the following to your app.js or directly inside a controller’s run() block:

if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('/service-worker.js')
    .then(function(reg) {
      console.log("Service Worker registered!", reg);
    })
    .catch(function(err) {
      console.error("Service Worker registration failed:", err);
    });
}

✅ Place this in the main JS entry point so it loads on every page.

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📄 Step 3: Create a Web App Manifest

Create a file called manifest.json in your root folder:

{
  "name": "AngularJS PWA App",
  "short_name": "NgJS PWA",
  "start_url": "/index.html",
  "display": "standalone",
  "background_color": "#ffffff",
  "theme_color": "#1976d2",
  "icons": [
    {
      "src": "images/icon-192.png",
      "sizes": "192x192",
      "type": "image/png"
    },
    {
      "src": "images/icon-512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ]
}

✅ Link it in index.html:

<link rel="manifest" href="manifest.json">

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🔐 Step 4: Ensure HTTPS Deployment

Service workers and PWAs require HTTPS (except on localhost). Deploy to:

• GitHub Pages
• Netlify
• Firebase Hosting
• Any HTTPS-enabled server

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📦 Optional: Add Background Sync & Push Notifications

Advanced service workers support:

• Background data syncing
• Push notifications using push and sync events
• IndexedDB integration for offline data storage

You can explore libraries like:

• Workbox.js – For managing complex caching
• Sw-precache / sw-toolbox – Legacy tools usable in AngularJS projects

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🧠 Real-World Use Cases

Use Case	Feature
To-do apps	Cache tasks for offline use
Product catalogs	Serve static product list
News readers	Prefetch articles
Booking forms	Sync requests when online
Portfolio apps	Enable installable experience

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🛠️ Best Practices for AngularJS PWAs

✔️ Keep service worker lean and simple
✔️ Test caching and fallbacks thoroughly
✔️ Use icons and manifest for installability
✔️ Keep cache versioning in mind
✔️ Serve app over HTTPS only

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📌 Summary – Recap & Next Steps

Even without native support, AngularJS can be enhanced to function as a Progressive Web App using service workers and a manifest. This enables offline access, caching, and mobile-like installability—all while keeping your existing AngularJS stack.

🔍 Key Takeaways:

• Add service-worker.js and register it in your AngularJS app
• Use a manifest file to define PWA appearance
• Cache important static assets and pages
• Deploy over HTTPS to enable full PWA features

⚙️ Real-world Relevance:
Perfect for modernizing legacy AngularJS apps into mobile-ready, offline-friendly applications without full migration.

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❓ FAQ – AngularJS Service Workers & PWA

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❓ Can AngularJS work with service workers?
✅ Yes. You can manually register and configure service workers in AngularJS projects.

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❓ Is AngularJS compatible with PWAs?
✅ AngularJS doesn’t natively support PWA features, but you can add service workers and manifest files manually.

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❓ Do PWAs need HTTPS?
✅ Yes. Service workers only run on secure origins (HTTPS) or localhost.

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❓ What libraries help with service workers in AngularJS?
✅ You can use Workbox.js, sw-toolbox, or sw-precache.

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