Steps to Build a Progressive Web App
Step 1: Setting Up Your Development Environment
Here are the primary tools you will want to set up your development environment:
- A code editor (such as Visual Studio Code, Atom, or Sublime Text)
- A local development server (such as Live Server extension in VS Code or Node.js with Express)
- A web browser (preferably Google Chrome or Firefox for their developer tools)
Step 1.1: Install Node.js and NPM:
Download and install Node.js. This will also install NPM. Verify the installation by running:
node -v
npm -v
Step 1.2: Initialize Your Project
Make a new project directory and initialize it with NPM:
mkdir my-pwa
cd my-pwa
npm init -y
Step 2: Building the User Interface(UI)
Start with the ‘index.html’ file. This will be the main entry point of your PWA. Here is an easy example:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,
initial-scale=1.0">
<title>My PWA</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<h2>Welcome to w3wiki</h2>
<p>This is a simple Progressive Web App example.</p>
<script src="app.js"></script>
</body>
</html>
Step 3: Adding Styles
Make a basic ‘styles.css’ file in the CSS directory to style your app:
body {
font-family: Helvetica, sans-serif;
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
margin: 0;
background-color: #f0f0f0;
}
h1 {
color: #333;
}
p {
color: #666;
}
Step 4: Use JavaScript to Show Your Information
Make a basic ‘app.js’ file:
console.log('Hello, w3wiki!');
Step 5: Create Web App Manifest
Make a ‘manifest.json’ file to characterize the app’s metadata:
{
"name": "My PWA",
"short_name": "PWA",
"start_url": ".",
"display": "standalone",
"background_color": "#ffffff",
"description": "A simple Progressive Web App example.",
"icons": [
{
"src": "icon.png",
"sizes": "192x192",
"type": "image/png"
}
]
}
Step 6: Add the manifest in your HTML file:
<link rel="manifest" href="manifest.json">
Step 7: Create and Fetch Assets
The service worker is a script that your browser runs in the background, separate from a web page, to manage caching and handle fetch requests. Create ‘sw.js’ file:
self.addEventListener('install', event => {
event.waitUntil(
caches.open('v1').then(cache => {
return cache.addAll([
'/',
'/index.html' ,
'/styles.css' ,
'/app.js' ,
'/manifest.json' ,
'/icon.png'
]);
})
);
});
self.addEventListener('fetch', event => {
event.respondWith(
caches.match(event.request).then(response => {
return response || fetch(event.request);
})
);
});
Step 7: Registering the Service Worker
In your ‘app.js’ file, register the service worker:
if ('serviceWorker' in navigator) {
window.addEventListener('load' , () => {
navigator.serviceWorker.register('/sw.js')
.then(registration => {
console.log('Service Worker registered with scope:' , registration.scope);
}).catch(error => {
console.log('Service Worker registration failed:' , error);
});
});
}
Step 8: Testing Your PWA
To test your PWA, you need to serve it over HTTPS. You can use basic Node.js server or any static file server. For development purposes, you can use ‘HTTP-server’ :
npm install -g http-server
http-server -p 8080
Navigate to http://localhost:8080 in your browser to see your PWA in action. Use Chrome DevTools to simulate different network conditions and test offline feature.
Step 9: Including Additional Features
Improve your PWA by adding push notifications, background sync, or improving performance using tools like Workbox, a set of libraries to simplify service worker development.
npm install workbox-cli --global
workbox generateSW
How to Build a Progressive Web App (PWA) from Scratch?
A Progressive Web App (PWA) is a kind of application software sent through the web, formed using standard web technologies such as HTML, CSS, and JavaScript. PWAs are planned to work on any platform that uses a standards-compliant browser, containing both desktop and portable devices.
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