Merge pull request RocketChat#334 from Shailesh351/sb_fix_pwa_caching

Fix First Time Caching Libs in PWA

client/importServiceWorker.js

@@ -2,17 +2,22 @@ import { Meteor } from 'meteor/meteor';
 
 Meteor.startup(() => {
 	if ('serviceWorker' in navigator) {
-	// if (navigator.serviceWorker.controller) {
-	//	console.log('Active service worker found, no need to register');
-	// } else {
 		// Register the service worker
 		navigator.serviceWorker
 			.register('sw.js', {
 				scope: './',
 			})
 			.then(function(reg) {
+				if (reg.installing) {
+					const sw = reg.installing || reg.waiting;
+					sw.onstatechange = function() {
+						if (sw.state === 'installed') {
+							// SW installed. Reload page.
+							window.location.reload();
+						}
+					};
+				}
 				console.log(`Service worker has been registered for scope: ${ reg.scope }`);
 			});
-	// }
 	}
 });