feat: enhance database indexing and optimize sync response handling

webapp/src/lib/api/vault-sync.ts

@@ -0,0 +1,31 @@
+import type { Cipher, Folder, Send } from '../types';
+import { parseJson, type AuthedFetch } from './shared';
+
+interface VaultSyncResponse {
+  ciphers?: Cipher[];
+  folders?: Folder[];
+  sends?: Send[];
+}
+
+const pendingSyncRequests = new WeakMap<AuthedFetch, Promise<VaultSyncResponse>>();
+
+export async function loadVaultSyncSnapshot(authedFetch: AuthedFetch): Promise<VaultSyncResponse> {
+  const existing = pendingSyncRequests.get(authedFetch);
+  if (existing) return existing;
+
+  const request = (async () => {
+    const resp = await authedFetch('/api/sync');
+    if (!resp.ok) throw new Error('Failed to load vault');
+    const body = await parseJson<VaultSyncResponse>(resp);
+    return body || {};
+  })();
+
+  pendingSyncRequests.set(authedFetch, request);
+  try {
+    return await request;
+  } finally {
+    if (pendingSyncRequests.get(authedFetch) === request) {
+      pendingSyncRequests.delete(authedFetch);
+    }
+  }
+}