Observable function encountering difficulties returning nested values

I've been working on a function that returns an observable.

test(id: int): Observable<Group>{
  this.http.get('test/').subscribe( (result:any) => {
     resultingVal = Group.fromJson(result.group);
  });
}

Right now, the function doesn't return anything, but my goal is to extract a specific property from a nested observable.

I am aiming for it to return returningVal, but I'm unsure of the best approach to achieve this nested value. Initially, I considered converting it into a promise, awaiting the result and then accessing the data. It worked, but it felt a bit clunky.

test(id: int): Observable<Group>{
  let returningVal = null
  let promise = this.http.get('test/').toPromise().then( result => {
     returningVal = Group.fromJson(result.group);
  });
  return from(Promise.all([promise]).then( _ => returningVal));
}

Is using promises in this manner the most effective solution, or is there a more elegant alternative resembling the initial code snippet? I personally find this workaround with promises somewhat hacky.

Answer №1

When dealing with your question, it appears that the test method is not returning an observable as expected. You simply need to make sure to return the get observable in order to solve this issue where test does not return an observable. By using the map operator from RxJS, you can transform the result by applying a function. It's important to note that in order to use any RxJS operator, you must utilize pipe as it acts as an RxJS operators composer.

test(id: int): Observable<Group>{
  return this.http.get('test/').pipe(map((result:any) => 
     Group.fromJson(result.group))
  );
}

In order to access the value, remember to subscribe to the test method.

test(10).subscribe(res => console.log(res))

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