Nats Jetstream library for NodeJS

The @abassade/events package provides a simplified interface for integrating NATS and JetStream messaging into your Node.js applications. This library exposes easy-to-use methods for connecting, publishing, and subscribing to messages, making it straightforward to incorporate these powerful messaging systems into your projects.

Installation

To install the package, use npm or yarn:

npm install @abassade/events

or

yarn add @abassade/events

Usage

Connecting

To use the library, first, you need to establish a connection to the NATS server and setup the topics/subjects with the stream.

import { nats, normalizeSubject } from '@abassade/events';

const natsUrl = 'nats://localhost:4222'; // you can replace this by your nats server url (host:port)
const subjects = ["provider.bank.account.created"]; // list of topics
const streamName = "Account-stream"; // stream name

async function start() {
    try {
         await nats.connect({ servers: "0.0.0.0:4222" });
         const jsm = await nats.nc.jetstreamManager();
         await nats.setupStream(subjects, streamName, jsm);
    } catch (error) {
        console.error('Failed to connect to NATS server:', error);
    }
}
start();

Publishing Messages

Once connected, you can publish messages to a subject.

import { nats, normalizeSubject } from '@abassade/events';


async function start() {
    try {
         await nats.publish(normalizeSubject("provider.bank.account.created"), {
            id: "sdzfsdfz",
            account_name: "John Doe",
         });
         console.log("published successful");
    } catch (error) {
        console.error('Failed to publish:', error);
    }
}

Subscribing to Messages

You can also subscribe to subjects to receive messages.

import { nats, normalizeSubject } from '@abassade/events';


async function start() {
    const postCreatedHandler = async (event: any, msg: JsMsg) => {
  try {
    console.log("event>>>", event); // you can make use of the events recieved
    msg.ack();
  } catch (error) {
    console.log(error);
  }
};
(async () => {
  await nats.subscribe(
    normalizeSubject("provider.polaris.account.created"),
    postCreatedHandler
  );
})();

API Reference

connect(natsUrl: string): Promise<void>

Establishes a connection to the NATS server.

• natsUrl: The URL of the NATS server.

publish(subject: string, message: any): Promise<void>

Publishes a message to the specified subject.

• subject: The subject to which the message will be published.
• message: The message to publish.

subscribe(subject: string, callback: (message: any) => void): Promise<void>

Subscribes to the specified subject to receive messages.

• subject: The subject to subscribe to.
• callback: A function that will be called with each received message.

Contributing

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

License

This project is licensed under the MIT License. See the LICENSE file for details.