'use strict'; self.onfetch = function(event) { if (event.request.url.indexOf('non-existent-file.txt') !== -1) { event.respondWith(new Response('Response from service worker')); } else if (event.request.url.indexOf('/iframe_page') !== -1) { event.respondWith(new Response( '\n' + '', { headers: [['content-type', 'text/html']] })); } else if (event.request.url.indexOf('/worker_script') !== -1) { event.respondWith(new Response( 'self.onmessage = (msg) => {' + ' const syncXhr = new XMLHttpRequest();' + ' syncXhr.open(\'GET\', msg.data.url, false);' + ' syncXhr.send();' + ' self.postMessage({' + ' status: syncXhr.status,' + ' responseText: syncXhr.responseText' + ' });' + '}', { headers: [['content-type', 'application/javascript']] })); } };