importScripts('sw-helpers.js'); async function getFetchResult(record) { try { await record.responseReady; } catch (e) { return { response: false, name: e.name, }; } return { response: true, }; } self.addEventListener('backgroundfetchabort', event => { event.waitUntil( event.registration.matchAll() .then(records => Promise.all(records.map(record => getFetchResult(record)))) .then(results => sendMessageToDocument({results}))); });