Node.js eventemitter

In Node.js, an EventEmitter is a class that allows you to implement an event-driven architecture in your applications. It provides a way to register and emit events that can be handled by other parts of your application.

The EventEmitter class is included in the Node.js core library, so you can use it in your applications without any additional installation.

Here's an example of how to use the EventEmitter class in a Node.js application:

const EventEmitter = require('events');

// create a new EventEmitter instance
const eventEmitter = new EventEmitter();

// register an event listener
eventEmitter.on('hello', () => {
  console.log('Hello, world!');
});

// emit an event
eventEmitter.emit('hello');

In this example, we create a new EventEmitter instance and register an event listener for the 'hello' event. When the 'hello' event is emitted, the listener function is called and logs 'Hello, world!' to the console.

You can also pass arguments to an event listener function when emitting an event:

// register an event listener with arguments
eventEmitter.on('greet', (name) => {
  console.log(`Hello, ${name}!`);
});

// emit the event with arguments
eventEmitter.emit('greet', 'John');

In this example, we register an event listener for the 'greet' event that takes a single argument, 'name'. When the 'greet' event is emitted with the argument 'John', the listener function is called and logs 'Hello, John!' to the console.