# Storage

Persist state with a signal: read it, write it, and it stays in storage.

## createLocalStorage

Returns a `Signal<T>` persisted to `localStorage`. Writes in other tabs/windows are synchronised automatically via `StorageEvent`.

```ts
import { createLocalStorage } from "elements-kit/utilities/storage";

const theme = createLocalStorage("theme", "light");

theme();        // "light"
theme("dark");  // persisted immediately
```

```ts
function createLocalStorage<T>(
  key: string,
  initialValue: T,
  options?: { serialise?: (v: T) => string; deserialise?: (raw: string) => T },
): Signal<T>
```

***

## createSessionStorage

Same as `createLocalStorage` but scoped to the current tab — no cross-tab sync.

```ts
import { createSessionStorage } from "elements-kit/utilities/storage";

const draft = createSessionStorage("draft", "");
```

```ts
function createSessionStorage<T>(key: string, initialValue: T, options?: StorageOptions<T>): Signal<T>
```

***

## See also

* [Promise](/primitives/promise)
* [Async](/primitives/async)