events.listenerCount(emitter, eventName)


稳定性: 0 - 弃用: 改为使用 emitter.listenerCount()

返回在给定 emitter 上注册的给定 eventName 的监听器数量的类方法。

const { EventEmitter, listenerCount } = require('node:events');
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// 打印: 2

Stability: 0 - Deprecated: Use emitter.listenerCount() instead.

A class method that returns the number of listeners for the given eventName registered on the given emitter.

const { EventEmitter, listenerCount } = require('node:events');
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2