# NatsStateStore API

State store backed by a NATS JetStream key-value bucket.

---
Canonical: /handbook/api/classes/_purista_nats-state-store.NatsStateStore/
Source: nats-state-store/src/NatsStateStore.impl.ts
Format: Markdown for agents
---

State store backed by a NATS JetStream key-value bucket.

Package: `@purista/nats-state-store`

## Signature

```typescript
class NatsStateStore
```

## Examples

```typescript
const store = new NatsStateStore({
  servers: 'nats://localhost:4222',
  keyValueStoreName: 'purista-state-store',
})

await store.setState('tenant.acme.prod.cart.session-123', { step: 'shipping' })
const state = await store.getState('tenant.acme.prod.cart.session-123')
await store.destroy()
```

## Members

### Constructors

- `new constructor(config?: { cacheTtl: number; enableCache: boolean; enableGet: boolean; enableRemove: boolean; enableSet: boolean; keyValueStoreName: string; ... })` — Creates a NATS JetStream-backed state store.

### Properties

- `config: { cacheTtl: number; enableCache: boolean; enableGet: boolean; enableRemove: boolean; enableSet: boolean; keyValueStoreName: string; ... }` — Store configuration including operation toggles.
- `connection: NatsConnection | undefined` — Active NATS connection, created lazily by `getStore`.
- `kv: KV | undefined` — Cached JetStream key-value bucket handle.
- `logger: Logger` — Child logger scoped to the store name.
- `name: string` — Store name used in logs and diagnostics.
- `sc: Codec<unknown>` — JSON codec used to encode and decode values in the key-value bucket.

### Methods

- `destroy(): Promise<void>` — Drains and closes the NATS connection and clears cached handles.
- `getState<StateNames>(...stateNames: StateNames): Promise<ObjectWithKeysFromStringArray<StateNames>>` — Get one or more state values by name.
- `getStateImpl<StateNames>(...stateNames: StateNames): Promise<ObjectWithKeysFromStringArray<StateNames>>` — Adapter-specific state lookup implementation.
- `getStore(): Promise<KV>` — Returns a healthy JetStream key-value bucket handle.
- `removeState(stateName: string): Promise<void>` — Remove one state value by name.
- `removeStateImpl(stateName: string): Promise<void>` — Adapter-specific state removal implementation.
- `setState(stateName: string, stateValue: unknown): Promise<void>` — Store or replace one state value.
- `setStateImpl(stateName: string, stateValue: unknown): Promise<void>` — Adapter-specific state write implementation.