How do you implement a message broker with RabbitMQ in Node.js?

Question

Accepted Answer

**RabbitMQ** — message broker for reliable async communication.

```javascript
const amqp = require("amqplib");

class MessageBroker {
    constructor(url) {
        this.url = url;
        this.connection = null;
        this.channel = null;
    }

async connect() {
        this.connection = await amqp.connect(this.url);
        this.channel = await this.connection.createChannel();
    }

async publish(exchange, routingKey, message) {
        await this.channel.assertExchange(exchange, "direct", { durable: true });
        this.channel.publish(
            exchange,
            routingKey,
            Buffer.from(JSON.stringify(message)),
            { persistent: true }
        );
    }

async consume(exchange, routingKey, handler) {
        await this.channel.assertExchange(exchange, "direct", { durable: true });
        const q = await this.channel.assertQueue("", { exclusive: true });
        await this.channel.bindQueue(q.queue, exchange, routingKey);

this.channel.consume(q.queue, async (msg) => {
            try {
                await handler(JSON.parse(msg.content.toString()));
                this.channel.ack(msg);
            } catch (err) {
                this.channel.nack(msg, false, true);
            }
        });
    }
}

// Usage
const broker = new MessageBroker("amqp://localhost");
await broker.connect();

// Publish
await broker.publish("orders", "order.created", { id: 123 });

// Consume
await broker.consume("orders", "order.created", async (msg) => {
    console.log("Order received:", msg);
});
```

Node.js: How do you implement a message broker with RabbitMQ in Node.js?