What does registerServiceWorker do in React JS?

Question

I'm a newbie in React and I was wondering what is the purpose of registerServiceWorker() in the following code?

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import registerServiceWorker from './registerServiceWorker';

ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker();

Answer 1

The service worker is a web API that helps you cache your assets and other files so that when the user is offline or on slow network, he/she can still see results on the screen, as such, it helps you build a better user experience, that's what you should know about service worker's for now. It's all about adding offline capabilities to your site.

React creates a service worker for you without your configuration by default. To learn more;

• Service Workers, MDN
• Service Workers, Google Web Fundamentals
• Simple offline site using service worker, CSS Tricks
• Server worker: A case study, Smashing Magazine

Answer 2

The service worker is to use the website data offline in case there is no network, it's like making PWA. Refer to this link PWA to know more about implementation and how to use registerServiceWorker().