我在一個(gè)角度項(xiàng)目上有一個(gè)奇怪的錯(cuò)誤，這些是代碼片段@Injectable()export class FirebaseMessagingService {    public tokenReceivedEmitter: any = new EventEmitter();    public messageReceivedEmitter: any = new EventEmitter();constructor(    private angularFireMessaging: AngularFireMessaging) {    this.angularFireMessaging.messaging.subscribe(        (messaging) => {            messaging.onMessage = messaging.onMessage.bind(messaging);            messaging.onTokenRefresh = messaging.onTokenRefresh.bind(messaging);        }    );}/** * request permission for notification from firebase cloud messaging * * @param userId userId */requestPermission(userId) {    this.angularFireMessaging.requestToken.subscribe(        (token) => {            this.tokenReceivedEmitter.emit({status: true, result: token});        },        (err) => {            this.tokenReceivedEmitter.emit({status: false, result: err});        }    );}/** * hook method when new notification received in foreground */receiveMessage() {    this.angularFireMessaging.messages.subscribe(        (payload) => {            this.messageReceivedEmitter.emit(payload);        });}這就是 firebase 消息服務(wù)，它在收到推送通知時(shí)發(fā)出令牌接收事件?，F(xiàn)在在組件中ngOnInit(){    // Subscribing to firebase token receive         this.firebaseTokenSubscription = this.messagingService.tokenReceivedEmitter.subscribe(            (message) => {                if (message.status) {                    const token = message.result;                    this.sendNotificationToken(token);                } else {                    this.snackBar.open(message.result, this.translate.instant('CLOSE')                     {duration:3000});                }        }    );}