Naive of cancelable switchMap

switch-map-cancel.ts

const { interval, of, from, pipe, empty } = Rx;
const { take, tap, share, takeUntil, switchMap,startWith, withLatestFrom, filter, concatMap, delay, merge } = RxOperators;

const $refresh = interval(1000).pipe(
  take(4),
  concatMap((x) => of(x).pipe(delay(x <= 2 ? 2000 : 1000))),
  share()
)

const cancel$ = of(-1).pipe(delay(5200), share());

$refresh.pipe(
  switchMap((r) => of(r).pipe(
    delay(1800),
    takeUntil(cancel$)
  ))
)