Node.js監聽器定義

Question

你會如何確定node.js中的監聽器？

它們是事件發射器對象，它偵聽某些事件發生，然後通知事件發射器或調用回調函數？

任何幫助理解

Answer 1

使用Event Emitter

下面是一個簡單的例子：

const EventEmitter = require('events'); 

class MyEmitter extends EventEmitter {} 

const myEmitter = new MyEmitter(); 

myEmitter.on('someCoolEvent',() => { // Here is where we are listening for event to occur 
    console.log('an event occurred!'); 
}); 


myEmitter.emit('someCoolEvent'); // here is how we emit the event