I have a component (not function) with local variables and states. How do I use rxjs in such situations, is it safe to use? Currently, I think it does not see state or local variables. This code is throwing with null reference for this.signedAPI.

this.validators$ = interval(validatorRefreshMillis)
        .pipe(
            tap(x => console.log('finalSignaturesxxx', x)),
            switchMap(() => {
                return from(this.callApi());
            }),
            takeUntil(this.destroy$)
        );

    this.validators$.
        pipe(
            takeUntil(this.destroy$)
        )
        .subscribe((validators) => {
            const signatures = this.setValidatorMappings(this.state.signatures, validators);
            console.log('finalSignaturesxxx', signatures, this.state.signatures, validators);
            this.setState({ signatures: signatures });
        })


callApi = (): Observable<Validator[]> => {
    return from(this.signedAPI.getData(
    ));
}