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Event-Driven Architecture in Node.js
Event Driven Architecture (EDA) has emerged as a powerful paradigm for building scalable, responsive, and loosely coupled systems. In Node.js, EDA plays a pivotal role, leveraging its asynchronous nature and event-driven capabilities to create efficient and robust applications. Let’s delve into the intricacies of Event-Driven Architecture in Node.js exploring its core concepts, benefits, and practical examples.
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Key Components in Node.js Event-Driven Architecture:
1. EventEmitter Module:
Central to Node.js’ event-driven architecture is the EventEmitter module, empowering the creation of objects capable of emitting and handling events. This module stands as a foundational element for integrating event-driven patterns into applications. Key functionalities of the EventEmitter include:
Event Registration:
Objects inheriting from EventEmitter can register event listeners for specific events they wish to track. This involves associating a function (listener) with a designated event name.
Event Emission:
Utilizing the emit() method within the EventEmitter, instances can emit events, indicating particular actions or state changes. This triggers the invocation of all registered listeners assigned to that event.
Custom Events:
Developers hold the capability to craft custom events in their applications, defining unique event names to signify diverse system actions or occurrences.
const EventEmitter = require('events');
class MyEmitter extends EventEmitter {}
const myEmitter = new MyEmitter();
// Event listener for 'customEvent'
myEmitter.on('customEvent', (arg1, arg2) => {
console.log('Event received with arguments:', arg1, arg2);
});
// Emitting the 'customEvent'
myEmitter.emit('customEvent', 'Hello', 'World');
In this example, a custom MyEmitter class is created, inheriting from EventEmitter. An event listener is added for the event ‘customEvent’, which logs the received arguments when the event is emitted using emit().