majiayu000 Mobile & PWA Development
Expert guidance for building Progressive Web Apps and mobile-optimized experiences that feel native.
When to Use This Skill
- Building Progressive Web Apps (PWAs)
- Implementing offline-first functionality
- Adding push notifications to web apps
- Creating installable web applications
- Optimizing for mobile devices
- Building with React Native basics
- Implementing mobile UX patterns
Progressive Web App Fundamentals
Web App Manifest
{
"name": "My Progressive Web App",
"short_name": "MyPWA",
"description": "A fast, reliable, and engaging app",
"start_url": "/",
"display": "standalone",
"background_color": "#ffffff",
"theme_color": "#3b82f6",
"orientation": "portrait-primary",
"icons": [
{
"src": "/icons/icon-72x72.png",
"sizes": "72x72",
"type": "image/png",
"purpose": "maskable any"
},
{
"src": "/icons/icon-96x96.png",
"sizes": "96x96",
"type": "image/png"
},
{
"src": "/icons/icon-128x128.png",
"sizes": "128x128",
"type": "image/png"
},
{
"src": "/icons/icon-144x144.png",
"sizes": "144x144",
"type": "image/png"
},
{
"src": "/icons/icon-152x152.png",
"sizes": "152x152",
"type": "image/png"
},
{
"src": "/icons/icon-192x192.png",
"sizes": "192x192",
"type": "image/png"
},
{
"src": "/icons/icon-384x384.png",
"sizes": "384x384",
"type": "image/png"
},
{
"src": "/icons/icon-512x512.png",
"sizes": "512x512",
"type": "image/png"
}
],
"screenshots": [
{
"src": "/screenshots/mobile.png",
"sizes": "750x1334",
"type": "image/png",
"form_factor": "narrow"
},
{
"src": "/screenshots/desktop.png",
"sizes": "1280x720",
"type": "image/png",
"form_factor": "wide"
}
],
"shortcuts": [
{
"name": "New Item",
"short_name": "New",
"url": "/new",
"icons": [{ "src": "/icons/new.png", "sizes": "96x96" }]
}
],
"categories": ["productivity", "utilities"],
"share_target": {
"action": "/share",
"method": "POST",
"enctype": "multipart/form-data",
"params": {
"title": "title",
"text": "text",
"url": "url",
"files": [
{
"name": "media",
"accept": ["image/*", "video/*"]
}
]
}
}
}
HTML Head Configuration
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
<!-- PWA Meta Tags -->
<meta name="theme-color" content="#3b82f6">
<meta name="mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
<meta name="apple-mobile-web-app-title" content="MyPWA">
<!-- Manifest -->
<link rel="manifest" href="/manifest.json">
<!-- Apple Touch Icons -->
<link rel="apple-touch-icon" href="/icons/icon-180x180.png">
<link rel="apple-touch-icon" sizes="152x152" href="/icons/icon-152x152.png">
<link rel="apple-touch-icon" sizes="180x180" href="/icons/icon-180x180.png">
<!-- Splash Screens for iOS -->
<link rel="apple-touch-startup-image" href="/splash/apple-splash-2048-2732.png"
media="(device-width: 1024px) and (device-height: 1366px)">
<title>My PWA</title>
</head>
Service Workers
Basic Service Worker Registration
// src/registerSW.ts
export async function registerServiceWorker(): Promise<ServiceWorkerRegistration | null> {
if (!('serviceWorker' in navigator)) {
console.log('Service workers not supported');
return null;
}
try {
const registration = await navigator.serviceWorker.register('/sw.js', {
scope: '/',
updateViaCache: 'none'
});
// Check for updates periodically
setInterval(() => {
registration.update();
}, 60 * 60 * 1000); // Every hour
// Handle updates
registration.addEventListener('updatefound', () => {
const newWorker = registration.installing;
if (!newWorker) return;
newWorker.addEventListener('statechange', () => {
if (newWorker.state === 'installed' && navigator.serviceWorker.controller) {
// New content available, show update prompt
dispatchEvent(new CustomEvent('swUpdate', { detail: registration }));
}
});
});
return registration;
} catch (error) {
console.error('SW registration failed:', error);
return null;
}
}
// Handle update prompt
export function promptUserToUpdate(registration: ServiceWorkerRegistration): void {
if (confirm('New version available! Reload to update?')) {
registration.waiting?.postMessage({ type: 'SKIP_WAITING' });
window.location.reload();
}
}
Complete Service Worker with Caching Strategies
// public/sw.js
const CACHE_VERSION = 'v1';
const STATIC_CACHE = `static-${CACHE_VERSION}`;
const DYNAMIC_CACHE = `dynamic-${CACHE_VERSION}`;
const IMAGE_CACHE = `images-${CACHE_VERSION}`;
// Assets to precache
const PRECACHE_ASSETS = [
'/',
'/index.html',
'/styles/main.css',
'/scripts/app.js',
'/offline.html',
'/icons/icon-192x192.png'
];
// Install event - precache static assets
self.addEventListener('install', (event) => {
event.waitUntil(
caches.open(STATIC_CACHE)
.then(cache => cache.addAll(PRECACHE_ASSETS))
.then(() => self.skipWaiting())
);
});
// Activate event - clean old caches
self.addEventListener('activate', (event) => {
event.waitUntil(
caches.keys()
.then(keys => Promise.all(
keys
.filter(key => key !== STATIC_CACHE && key !== DYNAMIC_CACHE && key !== IMAGE_CACHE)
.map(key => caches.delete(key))
))
.then(() => self.clients.claim())
);
});
// Fetch event - serve from cache with strategies
self.addEventListener('fetch', (event) => {
const { request } = event;
const url = new URL(request.url);
// Skip non-GET requests
if (request.method !== 'GET') return;
// Skip cross-origin requests
if (url.origin !== location.origin) return;
// API requests - Network First
if (url.pathname.startsWith('/api/')) {
event.respondWith(networkFirst(request, DYNAMIC_CACHE));
return;
}
// Images - Cache First with fallback
if (request.destination === 'image') {
event.respondWith(cacheFirst(request, IMAGE_CACHE));
return;
}
// Static assets - Cache First
if (PRECACHE_ASSETS.includes(url.pathname)) {
event.respondWith(cacheFirst(request, STATIC_CACHE));
return;
}
// Other requests - Stale While Revalidate
event.respondWith(staleWhileRevalidate(request, DYNAMIC_CACHE));
});
// Caching Strategies
async function cacheFirst(request, cacheName) {
const cached = await caches.match(request);
if (cached) return cached;
try {
const response = await fetch(request);
const cache = await caches.open(cacheName);
cache.put(request, response.clone());
return response;
} catch {
return caches.match('/offline.html');
}
}
async function networkFirst(request, cacheName) {
try {
const response = await fetch(request);
const cache = await caches.open(cacheName);
cache.put(request, response.clone());
return response;
} catch {
const cached = await caches.match(request);
return cached || new Response(JSON.stringify({ error: 'Offline' }), {
headers: { 'Content-Type': 'application/json' }
});
}
}
async function staleWhileRevalidate(request, cacheName) {
const cached = await caches.match(request);
const fetchPromise = fetch(request)
.then(response => {
const cache = caches.open(cacheName);
cache.then(c => c.put(request, response.clone()));
return response;
})
.catch(() => cached);
return cached || fetchPromise;
}
// Handle skip waiting message
self.addEventListener('message', (event) => {
if (event.data?.type === 'SKIP_WAITING') {
self.skipWaiting();
}
});
Workbox Integration (Recommended)
// sw.ts (using Workbox)
import { precacheAndRoute, cleanupOutdatedCaches } from 'workbox-precaching';
import { registerRoute, NavigationRoute } from 'workbox-routing';
import {
CacheFirst,
NetworkFirst,
StaleWhileRevalidate
} from 'workbox-strategies';
import { ExpirationPlugin } from 'workbox-expiration';
import { CacheableResponsePlugin } from 'workbox-cacheable-response';
declare const self: ServiceWorkerGlobalScope;
// Precache assets from build
precacheAndRoute(self.__WB_MANIFEST);
cleanupOutdatedCaches();
// Cache Google Fonts
registerRoute(
({ url }) => url.origin === 'https://fonts.googleapis.com' ||
url.origin === 'https://fonts.gstatic.com',
new StaleWhileRevalidate({
cacheName: 'google-fonts',
plugins: [
new ExpirationPlugin({ maxEntries: 30, maxAgeSeconds: 60 * 60 * 24 * 365 })
]
})
);
// Cache images
registerRoute(
({ request }) => request.destination === 'image',
new CacheFirst({
cacheName: 'images',
plugins: [
new ExpirationPlugin({ maxEntries: 100, maxAgeSeconds: 60 * 60 * 24 * 30 }),
new CacheableResponsePlugin({ statuses: [0, 200] })
]
})
);
// API calls - Network First
registerRoute(
({ url }) => url.pathname.startsWith('/api/'),
new NetworkFirst({
cacheName: 'api-cache',
plugins: [
new ExpirationPlugin({ maxEntries: 50, maxAgeSeconds: 60 * 5 })
]
})
);
// Navigation - Network First with offline fallback
registerRoute(
new NavigationRoute(
new NetworkFirst({
cacheName: 'navigations',
plugins: [
new CacheableResponsePlugin({ statuses: [200] })
]
}),
{
denylist: [/^\/_/, /\/api\//]
}
)
);
Push Notifications
Request Permission and Subscribe
// src/notifications.ts
interface PushSubscriptionData {
endpoint: string;
keys: {
p256dh: string;
auth: string;
};
}
export async function requestNotificationPermission(): Promise<NotificationPermission> {
if (!('Notification' in window)) {
console.log('Notifications not supported');
return 'denied';
}
const permission = await Notification.requestPermission();
return permission;
}
export async function subscribeToPush(): Promise<PushSubscriptionData | null> {
try {
const registration = await navigator.serviceWorker.ready;
// Check for existing subscription
let subscription = await registration.pushManager.getSubscription();
if (!subscription) {
// Create new subscription
const vapidPublicKey = import.meta.env.VITE_VAPID_PUBLIC_KEY;
subscription = await registration.pushManager.subscribe({
userVisibleOnly: true,
applicationServerKey: urlBase64ToUint8Array(vapidPublicKey)
});
}
// Send subscription to server
const subscriptionData: PushSubscriptionData = {
endpoint: subscription.endpoint,
keys: {
p256dh: arrayBufferToBase64(subscription.getKey('p256dh')),
auth: arrayBufferToBase64(subscription.getKey('auth'))
}
};
await fetch('/api/push/subscribe', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(subscriptionData)
});
return subscriptionData;
} catch (error) {
console.error('Push subscription failed:', error);
return null;
}
}
function urlBase64ToUint8Array(base64String: string): Uint8Array {
const padding = '='.repeat((4 - (base64String.length % 4)) % 4);
const base64 = (base64String + padding).replace(/-/g, '+').replace(/_/g, '/');
const rawData = window.atob(base64);
return Uint8Array.from([...rawData].map(char => char.charCodeAt(0)));
}
function arrayBufferToBase64(buffer: ArrayBuffer | null): string {
if (!buffer) return '';
return btoa(String.fromCharCode(...new Uint8Array(buffer)));
}
Handle Push in Service Worker
// In sw.js
self.addEventListener('push', (event) => {
const data = event.data?.json() ?? {
title: 'New Notification',
body: 'You have a new message'
};
const options = {
body: data.body,
icon: '/icons/icon-192x192.png',
badge: '/icons/badge-72x72.png',
image: data.image,
vibrate: [100, 50, 100],
data: {
url: data.url || '/',
timestamp: Date.now()
},
actions: data.actions || [
{ action: 'open', title: 'Open' },
{ action: 'dismiss', title: 'Dismiss' }
],
tag: data.tag || 'default',
renotify: true,
requireInteraction: data.requireInteraction || false
};
event.waitUntil(
self.registration.showNotification(data.title, options)
);
});
self.addEventListener('notificationclick', (event) => {
event.notification.close();
if (event.action === 'dismiss') return;
const url = event.notification.data?.url || '/';
event.waitUntil(
clients.matchAll({ type: 'window', includeUncontrolled: true })
.then(windowClients => {
// Focus existing window if available
for (const client of windowClients) {
if (client.url === url && 'focus' in client) {
return client.focus();
}
}
// Open new window
return clients.openWindow(url);
})
);
});
Offline Support
IndexedDB for Offline Data
// src/db.ts
import { openDB, DBSchema, IDBPDatabase } from 'idb';
interface MyAppDB extends DBSchema {
items: {
key: string;
value: {
id: string;
title: string;
content: string;
synced: boolean;
updatedAt: number;
};
indexes: { 'by-synced': boolean };
};
pendingSync: {
key: number;
value: {
id?: number;
type: 'create' | 'update' | 'delete';
collection: string;
data: unknown;
timestamp: number;
};
};
}
let dbPromise: Promise<IDBPDatabase<MyAppDB>>;
export function getDB(): Promise<IDBPDatabase<MyAppDB>> {
if (!dbPromise) {
dbPromise = openDB<MyAppDB>('my-app-db', 1, {
upgrade(db) {
// Items store
const itemStore = db.createObjectStore('items', { keyPath: 'id' });
itemStore.createIndex('by-synced', 'synced');
// Pending sync store
db.createObjectStore('pendingSync', { keyPath: 'id', autoIncrement: true });
}
});
}
return dbPromise;
}
// Save item locally
export async function saveItem(item: MyAppDB['items']['value']): Promise<void> {
const db = await getDB();
await db.put('items', { ...item, synced: false, updatedAt: Date.now() });
// Queue for background sync
await db.add('pendingSync', {
type: item.id ? 'update' : 'create',
collection: 'items',
data: item,
timestamp: Date.now()
});
// Request background sync
if ('serviceWorker' in navigator && 'sync' in ServiceWorkerRegistration.prototype) {
const registration = await navigator.serviceWorker.ready;
await registration.sync.register('sync-items');
}
}
// Get all items
export async function getAllItems(): Promise<MyAppDB['items']['value'][]> {
const db = await getDB();
return db.getAll('items');
}
// Get unsynced items
export async function getUnsyncedItems(): Promise<MyAppDB['items']['value'][]> {
const db = await getDB();
return db.getAllFromIndex('items', 'by-synced', false);
}
Background Sync
// In sw.js
self.addEventListener('sync', (event) => {
if (event.tag === 'sync-items') {
event.waitUntil(syncItems());
}
});
async function syncItems() {
const db = await openDB('my-app-db', 1);
const pendingItems = await db.getAll('pendingSync');
for (const item of pendingItems) {
try {
let endpoint = `/api/${item.collection}`;
let method = 'POST';
if (item.type === 'update') {
endpoint += `/${item.data.id}`;
method = 'PUT';
} else if (item.type === 'delete') {
endpoint += `/${item.data.id}`;
method = 'DELETE';
}
const response = await fetch(endpoint, {
method,
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(item.data)
});
if (response.ok) {
// Remove from pending queue
await db.delete('pendingSync', item.id);
// Mark item as synced
if (item.type !== 'delete') {
const existing = await db.get(item.collection, item.data.id);
if (existing) {
await db.put(item.collection, { ...existing, synced: true });
}
}
}
} catch (error) {
console.error('Sync failed for item:', item, error);
// Will retry on next sync
}
}
}
Mobile UX Patterns
Touch-Friendly Components
// src/components/TouchButton.tsx
import { useState, useRef, type ReactNode } from 'react';
interface TouchButtonProps {
children: ReactNode;
onClick: () => void;
className?: string;
haptic?: boolean;
}
export function TouchButton({
children,
onClick,
className = '',
haptic = true
}: TouchButtonProps) {
const [isPressed, setIsPressed] = useState(false);
const touchStartTime = useRef(0);
const handleTouchStart = () => {
setIsPressed(true);
touchStartTime.current = Date.now();
// Haptic feedback
if (haptic && navigator.vibrate) {
navigator.vibrate(10);
}
};
const handleTouchEnd = () => {
setIsPressed(false);
// Only trigger if not a long press
if (Date.now() - touchStartTime.current < 500) {
onClick();
}
};
return (
<button
className={`
min-h-[44px] min-w-[44px]
touch-manipulation select-none
transition-transform duration-150
${isPressed ? 'scale-95' : 'scale-100'}
${className}
`}
=> setIsPressed(true)}
=> setIsPressed(false)}
>
{children}
</button>
);
}
Pull-to-Refresh
// src/hooks/usePullToRefresh.ts
import { useState, useRef, useEffect } from 'react';
interface PullToRefreshOptions {
onRefresh: () => Promise<void>;
threshold?: number;
maxPull?: number;
}
export function usePullToRefresh({
onRefresh,
threshold = 80,
maxPull = 120
}: PullToRefreshOptions) {
const [pullDistance, setPullDistance] = useState(0);
const [isRefreshing, setIsRefreshing] = useState(false);
const startY = useRef(0);
const containerRef = useRef<HTMLDivElement>(null);
useEffect(() => {
const container = containerRef.current;
if (!container) return;
const handleTouchStart = (e: TouchEvent) => {
if (container.scrollTop === 0) {
startY.current = e.touches[0].clientY;
}
};
const handleTouchMove = (e: TouchEvent) => {
if (container.scrollTop > 0 || isRefreshing) return;
const currentY = e.touches[0].clientY;
const diff = currentY - startY.current;
if (diff > 0) {
e.preventDefault();
setPullDistance(Math.min(diff * 0.5, maxPull));
}
};
const handleTouchEnd = async () => {
if (pullDistance >= threshold && !isRefreshing) {
setIsRefreshing(true);
setPullDistance(threshold);
try {
await onRefresh();
} finally {
setIsRefreshing(false);
setPullDistance(0);
}
} else {
setPullDistance(0);
}
};
container.addEventListener('touchstart', handleTouchStart, { passive: true });
container.addEventListener('touchmove', handleTouchMove, { passive: false });
container.addEventListener('touchend', handleTouchEnd);
return () => {
container.removeEventListener('touchstart', handleTouchStart);
container.removeEventListener('touchmove', handleTouchMove);
container.removeEventListener('touchend', handleTouchEnd);
};
}, [pullDistance, isRefreshing, onRefresh, threshold, maxPull]);
return { containerRef, pullDistance, isRefreshing };
}
// Usage
function MyList() {
const { containerRef, pullDistance, isRefreshing } = usePullToRefresh({
onRefresh: async () => {
await fetchData();
}
});
return (
<div ref={containerRef} className="h-full overflow-y-auto">
{/* Pull indicator */}
<div
className="flex justify-center items-center transition-transform"
style={{
height: pullDistance,
transform: `translateY(${pullDistance > 0 ? 0 : -50}px)`
}}
>
{isRefreshing ? (
<Spinner />
) : pullDistance > 60 ? (
<span>Release to refresh</span>
) : (
<span>Pull to refresh</span>
)}
</div>
{/* List content */}
{items.map(item => <ListItem key={item.id} {...item} />)}
</div>
);
}
Swipe Actions
// src/components/SwipeableItem.tsx
import { useState, useRef, type ReactNode } from 'react';
interface SwipeableItemProps {
children: ReactNode;
onSwipeLeft?: () => void;
onSwipeRight?: () => void;
leftAction?: ReactNode;
rightAction?: ReactNode;
threshold?: number;
}
export function SwipeableItem({
children,
onSwipeLeft,
onSwipeRight,
leftAction,
rightAction,
threshold = 100
}: SwipeableItemProps) {
const [offset, setOffset] = useState(0);
const [isAnimating, setIsAnimating] = useState(false);
const startX = useRef(0);
const currentX = useRef(0);
const handleTouchStart = (e: React.TouchEvent) => {
startX.current = e.touches[0].clientX;
currentX.current = startX.current;
setIsAnimating(false);
};
const handleTouchMove = (e: React.TouchEvent) => {
currentX.current = e.touches[0].clientX;
const diff = currentX.current - startX.current;
// Limit swipe distance
const maxOffset = 150;
const limitedOffset = Math.sign(diff) * Math.min(Math.abs(diff), maxOffset);
// Only allow swipe if action exists
if ((diff > 0 && rightAction) || (diff < 0 && leftAction)) {
setOffset(limitedOffset);
}
};
const handleTouchEnd = () => {
setIsAnimating(true);
if (offset > threshold && onSwipeRight) {
onSwipeRight();
} else if (offset < -threshold && onSwipeLeft) {
onSwipeLeft();
}
setOffset(0);
};
return (
<div className="relative overflow-hidden">
{/* Background actions */}
<div className="absolute inset-0 flex">
{rightAction && (
<div className="flex-1 bg-green-500 flex items-center px-4">
{rightAction}
</div>
)}
{leftAction && (
<div className="flex-1 bg-red-500 flex items-center justify-end px-4">
{leftAction}
</div>
)}
</div>
{/* Swipeable content */}
<div
className={`relative bg-white ${isAnimating ? 'transition-transform duration-200' : ''}`}
style={{ transform: `translateX(${offset}px)` }}
>
{children}
</div>
</div>
);
}
React Native Basics
Setup and Structure
# Create new React Native project with Expo
npx create-expo-app@latest my-app --template blank-typescript
cd my-app
# Install common dependencies
npx expo install react-native-gesture-handler react-native-reanimated
npx expo install @react-navigation/native @react-navigation/stack
npx expo install expo-status-bar expo-constants
Basic Navigation
// App.tsx
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import { StatusBar } from 'expo-status-bar';
import HomeScreen from './screens/HomeScreen';
import DetailsScreen from './screens/DetailsScreen';
export type RootStackParamList = {
Home: undefined;
Details: { itemId: string };
};
const Stack = createStackNavigator<RootStackParamList>();
export default function App() {
return (
<NavigationContainer>
<StatusBar style="auto" />
<Stack.Navigator
initialRouteName="Home"
screenOptions={{
headerStyle: { backgroundColor: '#3b82f6' },
headerTintColor: '#fff',
headerTitleStyle: { fontWeight: 'bold' }
}}
>
<Stack.Screen
name="Home"
component={HomeScreen}
options={{ title: 'My App' }}
/>
<Stack.Screen
name="Details"
component={DetailsScreen}
options={({ route }) => ({ title: `Item ${route.params.itemId}` })}
/>
</Stack.Navigator>
</NavigationContainer>
);
}
Platform-Specific Code
// src/components/Button.tsx
import { Platform, TouchableOpacity, TouchableNativeFeedback, View, Text } from 'react-native';
interface ButtonProps {
title: string;
onPress: () => void;
}
export function Button({ title, onPress }: ButtonProps) {
const buttonContent = (
<View style={{
backgroundColor: '#3b82f6',
paddingVertical: 12,
paddingHorizontal: 24,
borderRadius: 8
}}>
<Text style={{ color: 'white', fontWeight: 'bold', textAlign: 'center' }}>
{title}
</Text>
</View>
);
if (Platform.OS === 'android') {
return (
<TouchableNativeFeedback
{buttonContent}
</TouchableNativeFeedback>
);
}
return (
<TouchableOpacity activeOpacity={0.7}>
{buttonContent}
</TouchableOpacity>
);
}
Install Prompt
Custom Install Prompt
// src/components/InstallPrompt.tsx
import { useState, useEffect } from 'react';
interface BeforeInstallPromptEvent extends Event {
prompt: () => Promise<void>;
userChoice: Promise<{ outcome: 'accepted' | 'dismissed' }>;
}
export function InstallPrompt() {
const [installPrompt, setInstallPrompt] = useState<BeforeInstallPromptEvent | null>(null);
const [isVisible, setIsVisible] = useState(false);
useEffect(() => {
const handler = (e: Event) => {
e.preventDefault();
setInstallPrompt(e as BeforeInstallPromptEvent);
setIsVisible(true);
};
window.addEventListener('beforeinstallprompt', handler);
// Check if already installed
if (window.matchMedia('(display-mode: standalone)').matches) {
setIsVisible(false);
}
return () => window.removeEventListener('beforeinstallprompt', handler);
}, []);
const handleInstall = async () => {
if (!installPrompt) return;
await installPrompt.prompt();
const { outcome } = await installPrompt.userChoice;
if (outcome === 'accepted') {
setIsVisible(false);
setInstallPrompt(null);
}
};
const handleDismiss = () => {
setIsVisible(false);
// Remember dismissal
localStorage.setItem('installPromptDismissed', Date.now().toString());
};
if (!isVisible) return null;
return (
<div className="fixed bottom-4 left-4 right-4 bg-white rounded-lg shadow-lg p-4 flex items-center gap-4 z-50 animate-slide-up">
<img src="/icons/icon-72x72.png" alt="App icon" className="w-12 h-12 rounded" />
<div className="flex-1">
<h3 className="font-semibold">Install Our App</h3>
<p className="text-sm text-gray-600">Get quick access from your home screen</p>
</div>
<button className="text-gray-400 p-2">
Not now
</button>
<button
className="bg-blue-500 text-white px-4 py-2 rounded-lg font-medium"
>
Install
</button>
</div>
);
}
Best Practices
Performance
Optimize First Paint
- Inline critical CSS
- Defer non-critical JavaScript
- Use skeleton screens
Touch Targets
- Minimum 44x44px touch targets
- Adequate spacing between targets
- Visual feedback on touch
Reduce Network Requests
- Bundle and minify assets
- Use service worker caching
- Lazy load images and routes
Accessibility
Zoom Support
- Never disable zoom
- Use relative units (rem, em)
- Test at 200% zoom
Reduced Motion
@media (prefers-reduced-motion: reduce) { * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; } }Color Contrast
- 4.5:1 minimum for normal text
- 3:1 minimum for large text
- Don't rely on color alone
Testing PWAs
Lighthouse Audit
npx lighthouse https://your-app.com --viewPWA Checklist
- HTTPS enabled
- Valid manifest.json
- Service worker registered
- Offline page works
- Install prompt shows
- Push notifications work