Angular Wait for boolean function to finish

Question

I am trying to fetch a list of users from my firestore database, and determine if the logged in user is an admin (i.e. he's in the list).

This is my code:

isAdmin(user: any): boolean {
    var col = this.afs.collection('admins');
    var docRef = col.doc('mini-admins');
    docRef.ref.get().then(function (doc) {
      if (doc.data().user == user)
        return true;
    }).catch(function (error) {
      console.log("Error getting document:", error);
    });
    return false;
}

However, even though the user is an admin, the function doesn't work. It looks like it isn't waiting for it to finish before proceeding.

How do I fix this?

Answer 1

It's not working because it's asynchronous. To make it work you need to change it slightly to:

isAdmin(user: any): Observable<boolean> {
    return new Observable(observer => { 
       var col = this.afs.collection('admins');
       var docRef = col.doc('mini-admins');
       docRef.ref.get().then(function (doc) {
          if (doc.data().user == user) {
              observer.next(true);
              observer.complete();
          }   
       }).catch(function (error) {
          observer.error(error);
          observer.complete();
          console.log("Error getting document:", error);
       });
    });
}

Then in your code when you want to check if the user is admin, call this function in the following way:

this.isAdmin(user).subscribe(success => { ... }, error => { ... });