A starting point to get you started with creating or converting your existing website/webapp into a Progressive Web App. Includes a service worker template.
A full example of all this is seen here
Remember the mainfest.json and serverworker.js need to be at the root.
Add the manifest.json reference to the index.html file’s head tag: ``
To get started with service workers, you first need to create a service worker’s JavaScript file. Will be placed in the root. You can see one here
You can add this file to load event in your javascript of html. You can see one here