Myujth

am tryind to add a service worker to my vuejs application. and this is what i get:
ServiceWorker registration failed: TypeError: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script.
i have searching a lot but i can't figure out where the problem is.
the reason of adding a service worker is to save the Token of any device logged in the app and be able to send them notification.
in index.html : static/manifest.json">

// app.js
var config = 
 apiKey: '',
 authDomain: '',
 databaseURL: '',
 projectId: '',
 storageBucket: '',
 messagingSenderId: ''
;
firebase.initializeApp(config);

const messaging = firebase.messaging();
let userToken = null,
 isSubscribed = false

window.addEventListener('load', () => 

 if ('serviceWorker' in navigator) 

 navigator.serviceWorker.register("firebase-messaging-sw.js", scope: "firebase-cloud-messaging-push-scope").then(function (registration) 
 const messaging = firebase.messaging();
 messaging.useServiceWorker(registration);

 ).catch(function (err) 
 // registration failed :(
 console.log('ServiceWorker registration failed: ', err);

 )
 else 
 
);

messaging.requestPermission().then(function() 
 //getToken(messaging);
 return messaging.getToken();
).then(function(token)
console.log(token);
)
.catch(function(err) 
console.log('Permission denied', err);
);


messaging.onMessage(function(payload)
console.log('onMessage: ',payload);
);

// firebase-messaging-sw.js

importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-messaging.js');
self.addEventListener('notificationclick', event => 
 console.log(event)

 event.notification.close()

 event.waitUntil(
 self.clients.openWindow('/')
 )
)
 var config = 
 apiKey: '',
 authDomain: '',
 databaseURL: '',
 projectId: '',
 storageBucket: '',
 messagingSenderId: ''
 ;

 firebase.initializeApp(config);
 const messaging = firebase.messaging();

//manifest.json

 "name": "Du",
 "short_name": "Du",
 "icons": [
 
 "src": "/static/img/icons/cro-icon-64x64.png",
 "sizes": "64x64",
 "type": "image/png"
 ,
 
 "src": "/static/img/icons/cro-icon-128x128.png",
 "sizes": "128x128",
 "type": "image/png"
 
 ],
 "start_url": "/",
 "display": "fullscreen",
 "orientation": "portrait",
 "background_color": "#2196f3",
 "theme_color": "#2196f3",
 "gcm_sender_id": ""

console project folder console2