Uncaught (in promise) TypeError: Request failed service worker

I want to add a view file inside cached but it doesn’t work.
How to call view Patch in cache?
//serviceworker.js.erb
ar CACHE_VERSION = ‘v1’;
var CACHE_NAME = CACHE_VERSION + ‘:sw-cache-’;

function onInstall(event) {
console.log(’[Serviceworker]’, “Installing!”, event);
event.waitUntil(
caches.open(CACHE_NAME).then(function prefill(cache) {
return cache.addAll([

// make sure serviceworker.js is not required by application.js
// if you want to reference application.js from here
'<%#= asset_path "application.js" %>',

'<%= asset_path "application.css" %>',

'/offline.html',
'/views/user/index.haml'

ar CACHE_VERSION = ‘v1’;

Is this a typo? ar instead of var or did you paste it in wrong?