chore(frontend): reduce redundancies

frontend/src/backend.js

@@ -157,6 +157,14 @@ export function sendAction(action, body = {}, callback = null) {
   return deferred.promise;
 }
 
+export async function act (action, body, { alert = null, cache = null } = {}) {
+  const res = await sendAction(action, body);
+  if (res.error) { ui.alert(`Error: ${res.error}`); return null; }
+  if (cache) invalidateCache(cache);
+  if (alert) ui.alert(alert);
+  return res;
+}
+
 export function ping() {
   if (socket && socket.readyState === WebSocket.OPEN) {
     const data = JSON.stringify({ path: 'ping' });