window.browser = window.browser || window.chrome browser.storage.local.get(["localstorage", "tmp"], r => { let localstorageJson = r.localstorage const frontend = r.tmp[0] const items = r.tmp[1] localstorageJson[frontend] = {} for (const item of items) { let tmp = localStorage.getItem(item) if (tmp) localstorageJson[frontend][item] = tmp } browser.storage.local.set({ localstorage: localstorageJson }) })