ydn-fetching-data-series-effect.ts

@Effect() actionX$ = this.updates$.pipe(
    ofType('ACTION_X'),
    map(toPayload),
    switchMap(payload => this.api.callApiX(payload).pipe(
        map(data => ({type: 'ACTION_X_SUCCESS', payload: data})),
        catch(err => Observable.of({type: 'ACTION_X_FAIL', payload: err})),
    )),
);
@Effect() actionY$ = this.updates$.pipe(
    ofType('ACTION_Y'),
    map(toPayload),
    withLatestFrom(this.store.select(state => state.someBoolean)),
    switchMap(([payload, someBoolean]) => {
        const callHttpY = v => {
            return this.api.callApiY(v).pipe(
                map(data => ({
                    type: 'ACTION_Y_SUCCESS', 
                    payload: data
                })),
                catch(err => Observable.of({
                    type: 'ACTION_Y_FAIL', 
                    payload: err
                })),
            );
        };
        
        if(someBoolean) {
            return callHttpY(payload);
        }
        return merge(
            of({type: 'ACTION_X', payload}),
            this.updates$.pipe(
                ofType('ACTION_X_SUCCESS', 'ACTION_X_FAIL'),
                first(),
                switchMap(action => {
                   if(action.type === 'ACTION_X_FAIL') {
                      return of({
                        type: 'ACTION_Y_FAIL', 
                        payload: 'Because ACTION_X failed.'
                      });
                    }
                    return callHttpY(payload);
                })
            ),
        );
    }),
);