Use await/async on shared directory

src/shared/settings/storage.js

@@ -1,17 +1,16 @@
 import DefaultSettings from './default';
 import * as settingsValues from './values';
 
-const loadRaw = () => {
-  return browser.storage.local.get('settings').then(({ settings }) => {
+const loadRaw = async() => {
+  let { settings } = await browser.storage.local.get('settings');
   if (!settings) {
     return DefaultSettings;
   }
   return Object.assign({}, DefaultSettings, settings);
-  });
 };
 
-const loadValue = () => {
-  return loadRaw().then((settings) => {
+const loadValue = async() => {
+  let settings = await loadRaw();
   let value = JSON.parse(DefaultSettings.json);
   if (settings.source === 'json') {
     value = settingsValues.valueFromJson(settings.json);
@@ -24,7 +23,6 @@ const loadValue = () => {
   return Object.assign({},
     settingsValues.valueFromJson(DefaultSettings.json),
     value);
-  });
 };
 
 const save = (settings) => {

src/shared/versions/index.js

@@ -13,13 +13,12 @@ const notificationClickListener = (id) => {
   browser.notifications.onClicked.removeListener(notificationClickListener);
 };
 
-const checkUpdated = () => {
-  return storage.load().then((prev) => {
+const checkUpdated = async() => {
+  let prev = await storage.load();
   if (!prev) {
     return true;
   }
   return manifest.version !== prev;
-  });
 };
 
 const notify = () => {

src/shared/versions/storage.js

@@ -1,7 +1,6 @@
-const load = () => {
-  return browser.storage.local.get('version').then(({ version }) => {
+const load = async() => {
+  let { version } = await browser.storage.local.get('version');
   return version;
-  });
 };
 
 const save = (version) => {