Events

Events

Events module is implementation of node events.

Module requires no configuration and usage is quite trivial:

import { Events } from 'node-mariner';

// Register the event listener
const PubSub = new Events();


// Register event
const sampleMessageListener = message => {
  console.log('You sent sample message', message)
}

PubSub.on('sample-message', sampleMessageListener)

// Check if listener is properly registered
console.log(PubSub.count()) // returns 1

// Emit the event
PubSub.emit('sample-message', 'this is dummy message')
// results in 'You sent sample message', 'this is a dummy message'

// Deregister the listener
PubSub.off('sample-message', sampleMessageListener);

// Check if listener is properly deregistered
console.log(PubSub.count()) // returns 0

Methods

Events provide 4 methods, with familiar publish-subscribe naming pattern:

method	arguments	description
on	(eventName, callback)	register listener for provided eventName
off	(eventName, callback)	unregister listener for provided eventName
emit	(eventName, payload)	emit an event for particular eventName
count	none	returns count<integer> of registered listeners to particular Event object