Unable to retrieve a boolean with the statement "return of(false)"

My objective is to retrieve data, store it, and return either true or false based on the operation outcome. Initially, I attempted to make the call and then use return of(true) to create an observable. The method I have is as follows.

setValidations(): Observable<boolean> {
  ...
  this.http.get<Validation[]>(url)
    .subscribe(
      suc => {
        environment.validations = suc;
        return of(true);
      },
      err => of(false)
    );
}

The error message informs me that I need to return something of type Observable. This leads me to believe that there might be a syntax issue. How can I correct this?

Edit based on answers/comments

setValidations(): Observable<boolean> {
  ...
  return this.http.get<Validation>(url)
    .pipe(
      map(_ => { console.log("Success"); return of(true); }),
      catchError => { console.log("Error"); return of(false); }
    );
}

I revised the method as demonstrated above. It appears to function properly, but I am receiving a warning about a variable named catchError being shadowed. This raises concerns that my approach may not be optimal.

Answer №1

In the case of an error, it is a callback that cannot be returned from; there is no way around it. In terms of semantics, once you reach that point, you are out of luck; according to definition, rxjs operates as a stream of events following a sequence of next*(complete|error). Therefore, when the first error (or more precisely, the only error) is encountered, things start falling apart. To manage potential errors and ensure your instance remains active, you need to utilize the catchError operator within your original Observer by using the provided documentation and examples.

setValidations(): Observable<boolean> {
  ...
  return this.http.get<Validation[]>(url)
    .pipe(
      tap(suc => environment.validations = suc),
      map(() => true),
      catchError(() => of(false))
    );
}

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