emitter.listeners()
Returns the array of listeners registered for an event, plus listenerCount.
Syntax
emitter.listeners(eventName) / emitter.listenerCount(eventName)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
eventName | string | symbol | Yes | The event to inspect. |
Returns
Function[] | number — listeners() returns a copy of the listener array; listenerCount() returns its length.
Examples
import { EventEmitter } from 'node:events';
const ee = new EventEmitter();
ee.on('go', () => {});
ee.on('go', () => {});
console.log(ee.listenerCount('go'));
Output
2
import { EventEmitter } from 'node:events';
const ee = new EventEmitter();
ee.once('boot', () => {});
console.log(ee.listeners('boot').length);
console.log(ee.eventNames());
Output
1
[ 'boot' ]
Notes
`listeners()` returns a snapshot copy, so mutating it does not affect
the emitter. Useful for diagnostics and detecting listener leaks.
`eventNames()` lists all events that currently have listeners.