content: import React from 'react'
  
  export default class extends React.PureComponent {
    componentDidMount () {
      if ('serviceWorker' in navigator) {
        navigator.serviceWorker
          .register('/service-worker.js')
          .then(registration => {
            console.log('service worker registration successful')
          })
          .catch(err => {
            console.warn('service worker registration failed', err.message)
          })
      }
    }
    render () {
      return (
        <p>Check the console for the Service Worker registration status.</p>
      )
    }
  }
  