feat(data): Added nats jetstream dependency

src/config.ts

@@ -10,6 +10,7 @@ export const config = {
     testing: process.env.NODE_ENV === "test",
     jwt_secret: process.env.JWT_SECRET || "secretjwtsecret",
     station_token_secret: process.env.STATION_TOKEN_SECRET || "",
+    nats_url: process.env.NATS_URL || "nats://localhost:4222",
     phone_validation_countrycode: getPhoneCodeLocale(),
     postalcode_validation_countrycode: getPostalCodeLocale(),
     version: process.env.VERSION || require('../package.json').version,

src/loaders/index.ts

@@ -1,4 +1,5 @@
 import { Application } from "express";
+import NatsClient from "../nats/NatsClient";
 import databaseLoader from "./database";
 import expressLoader from "./express";
 import openapiLoader from "./openapi";
@@ -9,6 +10,7 @@ import openapiLoader from "./openapi";
  */
 export default async (app: Application) => {
     await databaseLoader();
+    await NatsClient.connect();
     await openapiLoader(app);
     await expressLoader(app);
     return app;

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();