service.worker.active.js

self.addEventListener('activate', function (event) { 
    event.waitUntil( 
        caches.keys().then(function (cacheNames) {
            cacheNames.map(function (cacheName) {
                if (cacheName.indexOf(cacheVersion) < 0) { 
                    return caches.delete(cacheName);
                   } 
                }); 
            });
        }) 
    ); 
});