4

I tried to transform data before resolve by such way, but subscriber gets non-transformed data.

@Injectable()
export class OrderService {
    getAll(): Observable< Array<Order> > {
        let url = 'http://fakeapi.com';
        return this.http.get( url )
          .pipe(
            tap( (data: any) => {
                /*
                * MAKE DATA TRANSFORMATIONS HERE
                */
            }),
            catchError( (err: any, caught: Observable<{}>) => {
              console.log('error while GET : ' + url);
              console.warn(err);
              return caught;
            })
          );
    }
}

here is a subscriber:

this._orderService.getAll().subscribe( data => {
  this.orders = data;
  console.log('\nplanning-overview-page : _orderService.getAll : data ', data);
});
ame
  • 773
  • 9
  • 21

1 Answers1

7

map is the operator for transforming a value in an observable stream, and you have to make sure it returns a value.

map(data => {
    // do your transformations
    return data;
});
bryan60
  • 28,215
  • 4
  • 48
  • 65
  • It works, but there is a note: after I added map() the were arror "Property 'map' does not exist on type 'Observable' ". There is a solution of the error https://stackoverflow.com/a/41014638/7455192 – ame Nov 17 '17 at 14:57
  • yea, it needs to be imported like all the other operators, figured you knew since you were using tap already – bryan60 Nov 17 '17 at 15:00