i got an error like this:
core.js:6014 ERROR TypeError: Class constructor Observable cannot be invoked without 'new'
at new FirebaseObjectObservable (firebase_object_observable.js:16) at FirebaseObjectFactory (firebase_object_factory.js:7) at AngularFireDatabase.push../node_modules/angularfire2/database/database.js.AngularFireDatabase.object (database.js:18) at UserService.save (user.service.ts:12) at SafeSubscriber.next (app.component.ts:17) at SafeSubscriber.__tryOrUnsub (Subscriber.js:185) at SafeSubscriber.next (Subscriber.js:124) at Subscriber.next (Subscriber.js:72) at Subscriber.next (Subscriber.js:49 at Notification.observe (Notification.js:20)
import { Injectable } from '@angular/core';
import { AngularFireDatabase } from 'angularfire2/database';
import * as firebase from 'firebase';
@Injectable()
export class UserService {
constructor(private db: AngularFireDatabase) { }
save(user: firebase.User){
this.db.object('/users/' + user.uid).update({
name:user.displayName,
email:user.email
});
}
}