How to handle redirected URL for login authentication offline.

Hi Team,
I am using PWA in my angular-5 application, supported by angular-cli and I am using Keycloak for login authentication. The application works well offline, but one issue I am facing. While reloading the authenticator tries to find the login status from the Keycloak server and fails due to the internet connection.

Below is my service-worker:

`

var dataCacheName = 'resourceAllo-v1';
var cacheName = 'resourceAlloPWA-final-1';

var filesToCache = [
    '/',
    '/index.html',
    '/favicon.png',
    './app/app.component.html',
];

self.addEventListener('install', function(e) {
    console.log('[ServiceWorker] Install');
    e.waitUntil(
        caches.open(cacheName).then(function(cache) {
            console.log('[ServiceWorker] Caching app shell');
            return cache.addAll(filesToCache);
        })
    );
});

self.addEventListener('activate', function(e) {
    console.log('[ServiceWorker] Activate');
    e.waitUntil(
        caches.keys().then(function(keyList) {
            return Promise.all(keyList.map(function(key) {
                if (key !== cacheName && key !== dataCacheName) {
                    console.log('[ServiceWorker] Removing old cache', key);
                    return caches.delete(key);
                }
            }));
        })
    );
    
    return self.clients.claim();
});
self.addEventListener('opaqueredirect', function(e) {
    debugger
    console.log('[Service Worker] redirect ', e);
})

self.addEventListener('fetch', function(e) {
    console.log('[Service Worker] Fetch', e.request.url);
    var dataUrl = 'https://keycloak-server-connect/userinfo';
    var tokenUrl = 'https://keycloak-server-connect/protocol/openid-connect/token';
    var cssUrl = 'https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css';
    var keycloakUrl = 'https://keycloak-server-connect/auth/realms/abc/protocol/openid-connect/auth?client_id=service&redirect_uri=http%3A%2F%2Flocalhost%3A4200%2F&state=de9b09b0-d14e-408c-bf11-90c461861a57&nonce=a390644f-f3ca-4aff-be76-a23ef130e101&response_mode=fragment&response_type=code&scope=openid';

    if (e.request.url.indexOf(dataUrl) > -1) {
       
        e.respondWith(
            caches.open(cacheName).then(function(cache) {
                return fetch(e.request).then(function(response) {
                    cache.put(e.request.url, response.clone());
                    return response;
                });
            })
        );
    } else if (e.request.url.indexOf(cssUrl) > -1) {
        e.respondWith(
            caches.open(cacheName).then(function(cache) {
                return fetch(e.request).then(function(response) {
                    cache.put(e.request.url, response.clone());
                    return response;
                });
            })
        );
    } else if (e.request.url.indexOf(keycloakUrl) > -1) {
        e.respondWith(
            caches.open(cacheName).then(function(cache) {
                return fetch(e.request).then(function(response) {
                    cache.put(e.request.url, response.clone());
                    return response;
                });
            })
        )
    } else {
       
        var updateCache = function(request) {
            if (request.url != dataUrl && request.url != tokenUrl) {
                return caches.open(cacheName).then(function(cache) {
                    return fetch(request).then(function(response) {
                        console.log('[PWA Builder] add page to offline ' + response.url)
                        return cache.put(request, response);
                    });
                });
            }
        };

        e.waitUntil(updateCache(e.request.clone()));
        e.respondWith(
            caches.match(e.request).then(function(response) {
                return response || fetch(e.request);
            }).catch(function() {
                console.log('[Service Worker] event', e);
                // If both fail, show a generic fallback:
                return caches.match('/offline.html');
            })
        )
    }
});` 

And my main.js:

`if (navigator.serviceWorker.controller) {
            console.log('[PWA Builder] active service worker found, no need to register')
        } else {
            navigator.serviceWorker.register('service-worker.js', {
                scope: './'
            }).then(function(reg) {
                console.log('Service worker has been registered for scope:' + reg.scope);
            });
        }`

Please help me out on this. Let me know if any info is needed.

Read the supplied service-worker.js fetch handler and main.js registration first, then trace the Keycloak redirect and authentication-status requests during an offline reload. Confirm which request fails and define the expected login behavior before determining whether the change belongs in service-worker handling or application authentication.