IndexedDB Local Data

Use IndexedDB for offline records and outbox queues.

Minimal Helper

type LedgerEntry = {
  id: string;
  amount: number;
  note: string;
  synced: boolean;
  createdAt: string;
};

function openDb(): Promise<IDBDatabase> {
  return new Promise((resolve, reject) => {
    const request = indexedDB.open('ledger', 1);

    request.onupgradeneeded = () => {
      const db = request.result;
      db.createObjectStore('entries', { keyPath: 'id' });
      db.createObjectStore('outbox', { keyPath: 'id' });
    };

    request.onsuccess = () => resolve(request.result);
    request.onerror = () => reject(request.error);
  });
}

async function saveEntry(entry: LedgerEntry) {
  const db = await openDb();
  const tx = db.transaction(['entries', 'outbox'], 'readwrite');
  tx.objectStore('entries').put(entry);
  tx.objectStore('outbox').put({ id: entry.id, type: 'entry.create', payload: entry });
}

Sync-Safe Model

Add schema migrations before users have real data. Add export before you promise offline-first safety.