feat(data): Added nats jetstream dependency

src/nats/NatsClient.ts

@@ -0,0 +1,60 @@
+import consola from 'consola';
+import { connect, JetStreamClient, KV, KvOptions, NatsConnection } from 'nats';
+import { config } from '../config';
+
+/**
+ * Singleton NATS client.
+ * Call connect() once during app startup (after the DB loader).
+ * All other modules obtain the connection via getKV().
+ */
+class NatsClient {
+    private connection: NatsConnection | null = null;
+    private js: JetStreamClient | null = null;
+    private kvBuckets: Map<string, KV> = new Map();
+
+    /**
+     * Establishes the NATS connection and JetStream context.
+     * Must be called once before any KV operations.
+     */
+    public async connect(): Promise<void> {
+        this.connection = await connect({ servers: config.nats_url });
+        this.js = this.connection.jetstream();
+        consola.success(`NATS connected to ${config.nats_url}`);
+    }
+
+    /**
+     * Returns a KV bucket by name, creating it if it doesn't exist yet.
+     * Results are cached — repeated calls with the same name return the same instance.
+     */
+    public async getKV(bucketName: string, options?: Partial<KvOptions>): Promise<KV> {
+        if (this.kvBuckets.has(bucketName)) {
+            return this.kvBuckets.get(bucketName);
+        }
+        if (!this.js) {
+            throw new Error('NATS not connected. Call NatsClient.connect() first.');
+        }
+        const kv = await this.js.views.kv(bucketName, options);
+        this.kvBuckets.set(bucketName, kv);
+        return kv;
+    }
+
+    /**
+     * Gracefully closes the NATS connection.
+     * Call during app shutdown if needed.
+     */
+    public async disconnect(): Promise<void> {
+        if (this.connection) {
+            await this.connection.drain();
+            this.connection = null;
+            this.js = null;
+            this.kvBuckets.clear();
+            consola.info('NATS disconnected.');
+        }
+    }
+
+    public isConnected(): boolean {
+        return this.connection !== null;
+    }
+}
+
+export default new NatsClient();