Nested observables subscription

Question

I have the following code:

getUsers() {
    this.af.database.list(DB_URL)
    .map((users) => {
      return users.map((user) => {
        user.data = this.af.database.object(DB_URL_2).take(1);
        return user;
      });
    })
    .take(1)
    .subscribe((itemPrefs) => {
      this.users = users;
    })
  }

Which returns users array, where user.data is an observable (the user information).

How I can return the data of the user as an object and not as an observable? I tried to subscribe to my user.data but it still returning the observable:

return users.map((user) => {
            user.data = this.af.database.object(DB_URL_2).take(1)
.subscribe((data) => {
return data;
});
        return user;
      });

Pankaj Parkar · Accepted Answer · 2016-11-22 08:06:09Z

1

I think selectMany should do the trick, each inner function of ~~selectMany(RxJS4)~~ mergeMap(RxJS 5) would to return observable that will flatten. Which means that it will make sure that all inner data would be flatten.

Code

getUsers() {
    this.af.database.list(DB_URL)
    .mergeMap((user, i) => {
        return this.af.database.object(DB_URL_2).take(1).map(data => {
           user.data = data;
           return user;
        });
      });
    })
    .take(1)
    .subscribe((itemPrefs) => {
      this.users = users;
    })
}

edited Nov 22, 2016 at 8:06

answered Nov 21, 2016 at 18:12

Pankaj Parkar

136k23 gold badges241 silver badges307 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

TheUnreal Over a year ago

Any idea how I can import the selectMany operator in Angualr 2? I tried import 'rxjs/add/operator/selectMany';

Pankaj Parkar Over a year ago

@TheUnreal I guess it would be import { Observable } from 'rxjs/Observable'

TheUnreal Over a year ago

Property 'selectMany' does not exist on type 'FirebaseListObservable<any[]>'.

Pankaj Parkar Over a year ago

@TheUnreal sorry for inconvenience, selectMany was used in rxjs4, since we are using RxJS5 it became mergeMap. Please let me know if it works for you.

Pankaj Parkar Over a year ago

@TheUnreal could you please confirm that does it work for you or not?

|

Collectives™ on Stack Overflow

Nested observables subscription

1 Answer 1

8 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Your Answer

Sign up or log in

Post as a guest

Related