Rxjs BehaviorSubject error handling when used with mergemap - angular7

Question

I have the following code
#Injectable()
export class ReceptionService {
private generalInfoDataSrc$ = new BehaviorSubject<any>(null);
public generalInfoData = this.generalInfoDataSrc$.asObservable();
setGeneralInfo(dataSrc: GeneralInfoMModal) {
this.generalInfoDataSrc$.next(dataSrc);
}
}
From my component1 I will set the above as
OnSelect(patient: any) {
let generalInfo = new GeneralInfoMModal();
generalInfo.id = patient.id;
// some other code here
// this.recepService.setGeneralInfo(generalInfo);
}
// from component2
//
ngOnInit() { getPatientDetails() }
getPatientDetails() {
this.receptionService.generalInfoData.pipe(mergeMap(response => {
if (response && response.id) {
this.loading = true;
return this.receptionService.get('User/Get' + response.id, this.sourceobj);
} else {
return of(null);
}
}), takeUntil(this.unsubscribe$)).subscribe(response => {
this.patient = response;
this.loading = false;
}, error => {
this.loading = false;
// this.utility.showMsg('An error occurred while getting user.')
}, () => {
})
}
Every things works well. I keep on selecting a user thereby calling the User/Get api. But if in case if the api returns an error then error part is executed after which when there is a change in behaviorsubject(user is selected) it doesn't call the User/Get. Is there other way of handling errors with behaviorsubject or any other approach to handle the idea. How a behaviorsubject should be used in such a case.

Answer 1

If you are using the same behavior subject over and over again, and if there is an error, you need to set the behavior subject back to null, so that when the next user is set, it will get the latest value.
Try something like this:
getPatientDetails() {
this.receptionService.generalInfoData.pipe(mergeMap(response => {
if (response && response.id) {
this.loading = true;
return this.receptionService.get('User/Get' + response.id, this.sourceobj);
} else {
return of(null);
}
}), takeUntil(this.unsubscribe$)).subscribe(response => {
this.patient = response;
this.loading = false;
}, error => {
this.loading = false;
///////////////////////////////// ADD THIS LINE ///////////////////////
this.recepService.setGeneralInfo(null);
// this.utility.showMsg('An error occurred while getting user.')
}, () => {
})