register-sw.js

if ('serviceWorker' in navigator) {
  window.addEventListener('load', function() {
    navigator.serviceWorker.register('/sw.js')
      .then(function(registration) {
      
        // Registration was successful
        console.log('ServiceWorker registration successful with    scope: ', registration.scope);
      }).catch(function(err) {
      
        // registration failed :(
        console.log('ServiceWorker registration failed: ', err);
      });
  });
}