EventEmitter.on - Node documentation
method EventEmitter.on

Usage in Deno

import { type EventEmitter } from "node:events";
EventEmitter.on<K>(
eventName: Key<K, T>,
listener: Listener1<K, T>,
): this

Adds the listener function to the end of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventNameand listener will result in the listener being added, and called, multiple times.

server.on('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. Theemitter.prependListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.on('foo', () => console.log('a'));
myEE.prependListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Type Parameters

K

Parameters

eventName: Key<K, T>

The name of the event.

listener: Listener1<K, T>

The callback function

Return Type

this