psuedo code

clickEvent$ = fromEvent(window, 'click').pipe(// do some conversion);

outofbound$: Observable<[boolean, boolean]> = clickEvent$.pipe(//do some calculation);

offset$: Observable<number> = clickEvent$.pipe(// do some calculation);  // this never triggered

finalresult$ = outofbound$.switchmap( //check some predicate and return offset$ or other stream);