Which file takes care of caching and updating files for offline capability in a React app?

Which file takes care of caching and updating files for offline capability in a React app?

• A. registerServiceWorker.js
• B. manifest.json
• C. index.html
• D. server.js

Answer: (A)

Offline capability in a React app is enabled by a service worker, a script that can cache assets and serve them when the network is unavailable, and then update those cached files when a new version comes in. The file that takes care of wiring this up is the service worker registration file. It loads the service worker, hooks into its lifecycle (install, activate, fetch), and ensures the app uses the cached resources when offline while also allowing updates to come in when online again. The actual caching logic lives in the service worker script itself, but without the registration file, that service worker wouldn’t be activated at all. The other options don’t manage offline caching: manifest.json describes how the app should behave when installed as a PWA; index.html is the app’s entry HTML file; server.js runs on the backend and isn’t involved in client-side offline caching.

Offline capability in a React app is enabled by a service worker, a script that can cache assets and serve them when the network is unavailable, and then update those cached files when a new version comes in. The file that takes care of wiring this up is the service worker registration file. It loads the service worker, hooks into its lifecycle (install, activate, fetch), and ensures the app uses the cached resources when offline while also allowing updates to come in when online again. The actual caching logic lives in the service worker script itself, but without the registration file, that service worker wouldn’t be activated at all.

The other options don’t manage offline caching: manifest.json describes how the app should behave when installed as a PWA; index.html is the app’s entry HTML file; server.js runs on the backend and isn’t involved in client-side offline caching.