title: adding service worker to reactjs app
body: <p>I'm about the create a small single page reactjs app that fetches data from 3rd API (let's say  youtube videos, so those will be displayed). So I don't need any backend at all, but I'd like to make it offline first with service workers, so if there is no connection it will still display some cached data by default. For this I will use service workers, but don't really know if I have to add any other library or I can just use it right away. </p>
  
  <p>Could somebody tell me what the best way is to implement this small offline-first react app?</p>