@statesync/persistence

---

@statesync/persistence / createSessionStorageBackend

Function: createSessionStorageBackend()

function createSessionStorageBackend<T>(options): StorageBackend<T>;

Defined in: persistence/src/storage/session-storage.ts:94

Creates a StorageBackend that persists snapshot data using the browser's sessionStorage API.

Unlike localStorage, data stored in sessionStorage is scoped to the current browser tab and is automatically cleared when the tab or window is closed. This makes it ideal for temporary state that should not survive across sessions, such as form drafts, wizard progress, or transient UI state.

Each browser tab maintains its own independent sessionStorage, so data is not shared between tabs even within the same origin.

Browser compatibility: Supported in all modern browsers. Requires a secure context (HTTPS) in some browsers for full functionality. Not available in Web Workers or Service Workers.

Storage limits: sessionStorage has a ~5MB per-origin limit in most browsers. The storage is synchronous under the hood but exposed through an async interface for API consistency with other backends.

Type Parameters

Type Parameter	Description
T	The type of the state data stored within snapshot envelopes.

Parameters

Parameter	Type	Description
options	SessionStorageBackendOptions	Configuration options for the sessionStorage backend.

Returns

StorageBackend<T>

A StorageBackend instance backed by sessionStorage.

Throws

Throws a descriptive error wrapping QuotaExceededError when the sessionStorage quota is exceeded during a save operation.

Throws

Throws a descriptive error when stored data cannot be deserialized during a load operation (e.g., corrupted or incompatible data).

Examples

const storage = createSessionStorageBackend<MyState>({ key: 'temp-state' });

// Save a snapshot (cleared when tab closes)
await storage.save({ revision: '1', data: { step: 3 } });

// Load the snapshot
const snapshot = await storage.load();
console.log(snapshot?.data.step); // 3

// Clear stored data manually
await storage.clear();

const storage = createSessionStorageBackend<MyState>({
  key: 'temp-state',
  serialize: (snapshot) => btoa(JSON.stringify(snapshot)),
  deserialize: (data) => JSON.parse(atob(data)),
});