once

fun <T : EventEmitter, P : JsTuple> T.once(type: EventType<T, P>, listener: (P) -> Unit)(source)

Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

server.once('connection', (stream) => {
console.log('Ah, we have our first user!');
});

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

By default, event listeners are invoked in the order they are added. The emitter.prependOnceListener() 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.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
// b
// a

Since

v0.3.0

Parameters

type

The name of the event.

listener

The callback function


suspend fun <P : JsTuple> EventInstance<P>.once(): P(source)