events

EventEmitter creation

This code sample shows how to import the 'events' package and create a new instance of an EventEmitter.

const EventEmitter = require('events');
const myEmitter = new EventEmitter();

Event listening

This code sample demonstrates how to listen for an 'event' and execute a callback function when the event is emitted.

myEmitter.on('event', () => {
  console.log('an event occurred!');
});

Event emitting

This code sample shows how to emit an 'event', which will trigger any associated event listeners.

myEmitter.emit('event');

Once listener

This code sample demonstrates how to set up a listener that will only be called once for the next time the event is emitted.

myEmitter.once('event', () => {
  console.log('this event will be logged only once');
});

Removing listeners

This code sample shows how to remove a specific listener from an event.

const callback = () => console.log('event occurred');
myEmitter.on('event', callback);
// ...
myEmitter.removeListener('event', callback);