// use synced storage if supported, fall back to local const storage = browser.storage.sync || browser.storage.local; const setEndpoint = (endpoint) => { return storage.set({endpoint}); } const getEndpoint = () => { return new Promise((resolve, reject) => { storage.get("endpoint").then((res) => { if (res && res.endpoint) { resolve(res.endpoint); } else { resolve(null); } }, (err) => { resolve(null); }); }); }