The resume mentions PWA performance optimization. What is PWA, how is it decoded, and how does it differ from SPA? How to turn an SPA into a PWA?

PWA (Progressive Web App) is a progressive web application that combines the best qualities of a website and a native app. It runs in the browser but can work offline, be installed on a device, and send push notifications.

Differences between PWA and SPA (Single Page Application):

• SPA is an architectural approach where the application loads a single page and dynamically updates content without reloading.
• PWA is a set of technologies and practices that make a web application more like a native app: offline access, installation, push notifications, high performance.

That is, SPA is about the structure of the application, and PWA is about the user experience and capabilities.

How to turn an SPA into a PWA:

1. Add a Service Worker — a script that runs in the background and caches resources for offline mode.
2. Create a Web App Manifest — a JSON file with metadata (icons, name, theme color) that allows installing the app on a device.
3. Ensure HTTPS — a mandatory condition for Service Worker to work.
4. Optimize performance and loading so that the app starts quickly.

Example of a manifest (manifest.json):

{
  "name": "My PWA",
  "short_name": "PWA",
  "start_url": "/index.html",
  "display": "standalone",
  "background_color": "#ffffff",
  "theme_color": "#000000",
  "icons": [
    {
      "src": "icon-192.png",
      "sizes": "192x192",
      "type": "image/png"
    },
    {
      "src": "icon-512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ]
}

Thus, PWA extends the capabilities of SPA, making the web application more convenient and accessible for users.