Módulo de eventos de Node.js
Ejemplo
Cree un detector de eventos para un evento llamado "gritar", luego provoque el evento:
var events = require('events');
var eventEmitter = new
events.EventEmitter();
eventEmitter.on('scream', function() {
console.log('A scream is detected!');
});
eventEmitter.emit('scream');
Definición y uso
El módulo Eventos proporciona una forma de trabajar con eventos.
En Node.js, todos los eventos son una instancia del objeto EventEmitter
Sintaxis
La sintaxis para incluir el módulo Eventos y crear un EventEmitter en su aplicación:
var events = require('events');
var eventEmitter = new events.EventEmitter();
Propiedades y métodos de EventEmitter
Method | Description |
---|---|
addListener() | Adds the specified listener |
defaultMaxListeners | Sets the maximum number of listeners allowed for one event. Default is 10 |
emit() | Call all the listeners registered with the specified name |
eventNames() | Returns an array containing all registered events |
getMaxListeners() | Returns the maximum number of listeners allowed for one event |
listenerCount() | Returns the number of listeners with the specified name |
listeners() | Returns an array of listeners with the specified name |
on() | Adds the specified listener |
once() | Adds the specified listener once. When the specified listener has been executed, the listener is removed |
prependListener() | Adds the specified listener as the first event with the specified name |
prependOnceListener() | Adds the specified listener as the first event with the specified name, once. When the specified listener has been executed, the listener is removed |
removeAllListeners() | Removes all listeners with the specified name, or ALL listeners if no name is specified |
removeListener() | Removes the specified listener with the specified name |
setMaxListeners() | Sets the maximum number of listeners allowed for one event. Default is 10 |