我在一個函數中有兩個類，由于某種原因，第二個函數this沒有被正確識別。類是Emitter和Receiver。我試圖弄清楚為什么this這里沒有被正確拾取。該日志包含在以下代碼中：const chat = (messages) => {  class Emitter {    constructor(messages = []) {      this.messages = messages;      this.event = () => {};    }    setEvent(fn) {      this.event = fn;    }    trigger() {      this.messages.forEach(message => this.event(message));    }  }  class Receiver {    constructor() {      this.messages = [];      // this prints correctly here      ---> Receiver { messages: [] }      console.log('this  ===> ', this)    }    ping(message) {      console.log('this ===>', this)      // this here prints the following      this ===> Emitter {        messages: [ 'Hi', 'Hola', 'Bonjour', 'Hi' ],        event: [Function: ping] }          this.messages.push(message);       }  }  const myReceiver = new Receiver();  const myEmitter = new Emitter(messages);  myEmitter.setEvent(myReceiver.ping);  myEmitter.trigger();  return myReceiver.messages;};