Technical Leadership and Architectural Influence Questions

type OptimisticUpdate<TData, TVariables> = (vars: TVariables, current: TData | undefined) => TData;
type Rollback<TData> = (prev: TData | undefined) => void;

function useOptimisticMutation<TData, TVariables>({
  mutationFn,
  optimisticUpdate,
  rollback,
  onConflict,
  onError,
  onSuccess,
  cacheClient, // e.g., QueryClient from react-query or ApolloClient
}: {
  mutationFn: (vars: TVariables) => Promise<TData>;
  optimisticUpdate: OptimisticUpdate<TData, TVariables>;
  rollback?: Rollback<TData>;
  onConflict?: (local: TData, remote: TData) => Promise<'merge' | 'overwrite' | 'reject'>;
  onError?: (error: unknown, vars: TVariables, context?: any) => void;
  onSuccess?: (data: TData, vars: TVariables) => void;
  cacheClient?: any;
}) : {
  mutate: (vars: TVariables) => Promise<void>;
  status: 'idle' | 'optimistic' | 'committing' | 'success' | 'error';
  error?: unknown;
  rollback: () => void;
}

// sss-channel.js
const bc = new BroadcastChannel('mfe-state');
export function publishDelta(key, delta) {
  bc.postMessage({ key, delta, ts: Date.now() });
}
export function subscribe(handler) {
  bc.onmessage = e => handler(e.data);
}

// parent -> child
childWindow.postMessage({ type:'SSS_HANDSHAKE', originId:'app-A' }, childOrigin);
// child verifies and replies with public channel id and HMAC