Type 'Observable<unknown[]>' is not assignable to type 'Observable<User[]>'

Issue

I got this error:

Type 'Observable<unknown[]>' is not assignable to type 'Observable<User[]>'.

I'm trying to fetch data from firestore.

I use Observable for the first time (I watch some videos about observable, but here I can't use why I do not understand). Can you help me?

by the way, user is this:

export interface User {
  email: string;
  uid: string;
}

my codes here:

  usersCollection: AngularFirestoreCollection<User>;
  users: Observable<User[]>;
   constructor(public auth: AngularFireAuth, public db: AngularFirestore) {
    **this.users(problem here)** = this.db.collection("users").valueChanges();
  }

Solution

You can fix it by passing the User type as a generic parameter to the collection like the following:

this.users = this.db.collection<User>("users").valueChanges();

This will return Observable<User[]> from the valueChanges.

Answered By - Amer