greenwebsites-event-dispatcher

🚀 Event Dispatcher

A lightweight Node.js package for dispatching structured events to a middleware API.

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📌 Features

✅ Standardized event format with metadata
✅ Automatic eventId and correlationId generation
✅ Lightweight, few dependencies (only uses uuid jest)
✅ Works with any HTTP-based middleware API

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🛠 Installation

Install via npm:

npm install greenwebsites-event-dispatcher 

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📌 Usage

1️⃣ Import and Initialize the Dispatcher

import { EventDispatcher } from "greenwebsites-event-dispatcher";

// Initialize with middleware URL from .env or provide a URL
const dispatcher = new EventDispatcher();

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2️⃣ Sending an Event

async function sendEvent() {
  await dispatcher.sendEvent("user-service", "UserSignedUp", {
    userId: "12345",
    email: "[e-mail]",
  });
}

sendEvent().catch(console.error);

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3️⃣ Sending an Event with Correlation ID

async function sendWithCorrelation() {
  await dispatcher.sendEvent("billing-service", "InvoiceGenerated", {
    invoiceId: "INV-5678",
    amount: 150.00,
    status: "pending",
  }, "req-98765"); // Correlation ID for tracking
}

sendWithCorrelation().catch(console.error);

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📌 Error Handling & Retries

If the middleware is unreachable, the dispatcher will log the error.

To implement retry logic, wrap it in a function like this:

async function sendWithRetries(dispatcher, source, type, detail, retries = 3) {
  for (let i = 0; i < retries; i++) {
    try {
      await dispatcher.sendEvent(source, type, detail);
      return;
    } catch (error) {
      console.error(`Attempt ${i + 1} failed. Retrying...`);
      if (i === retries - 1) throw error;
      await new Promise(resolve => setTimeout(resolve, (i + 1) * 1000));
    }
  }
}

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📌 Example Scripts

You can run example scripts included in the package:

• Send a test event

  npm run example:send

• Send with a correlation ID

  npm run example:correlation

• Test error handling

  npm run example:failure

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🛠 Development

1️⃣ Clone the Repository

git clone https://github.com/yourusername/event-dispatcher.git
cd event-dispatcher
npm install

2️⃣ Running Tests

npm test

3️⃣ Building the Project

npm run build

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📌 Contributing

We welcome contributions! To contribute:

1. Fork the repo and create a new branch.
2. Make your changes and add tests.
3. Open a pull request.

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📌 License

📜 This package is MIT licensed.

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