Type 'Subscription' is missing the following properties from type 'BehaviorSubject<CalendarEvent<{ book: Book; }>[]>'

I try to get data using Subscription but it return error Type 'Subscription' is missing the following properties from type 'BehaviorSubject<CalendarEvent<{ book: Book; }>[]>'. The error come from this part this.events$ =

I arrange code like this.

auth.service

getSeating() {
    return this.http.get<any>(environment.apiBaseUrl+environment.path+`/data/getseating`)
    .pipe(
      tap(res => this.setSession),
      shareReplay()
    );
  }

commonce.service

_getSeating(){
    this.loading.present();
    this.auth.getSeating()
    .pipe(take(1))
    .subscribe(
      res => {
        // console.log(res)
        if (res['status'].code == 0) {
          this.bookSeatList$.next(res['seating']);
        }else {
          this.toastMsg(res['status'].message);
        }
        this.loading.dismiss();
      },
      error => {
        this.loading.dismiss();
      }
    )
  }

in my component page I arrange like this

events$: BehaviorSubject<CalendarEvent<{ book: Book }>[]>;

ngOnInit() {
  this.fetchEvents();
}

fetchEvents() {
      const getStart: any = {
        month: startOfMonth,
        week: startOfWeek,
        day: startOfDay,
      }[this.view];
  
      const getEnd: any = {
        month: endOfMonth,
        week: endOfWeek,
        day: endOfDay,
      }[this.view];
      
      this.events$ = this.commonService.bookSeatList$.subscribe(res=>{
        console.log(res);
        return res.map((book: Book) => {
          console.log(book);
        return {
          title: book.earlyBird,
          start: new Date(
            book.date + getTimezoneOffsetString(this.viewDate)
          ),
          color: colors.yellow,
          allDay: true,
          
        };
      });
    })
    }

value from this.bookSeatList$.next(res['seating']);

`

0: {date: "2021-04-14", earlyBird: 100, standard: 130}
1: {date: "2021-04-15", earlyBird: 100, standard: 130}
2: {date: "2021-05-11", earlyBird: 0, standard: 200}
3: {date: "2021-05-12", earlyBird: 0, standard: 200}
4: {date: "2021-04-16", earlyBird: 98, standard: 130}
5: {date: "2021-04-17", earlyBird: 94, standard: 130}
6: {date: "2021-04-19", earlyBird: 99, standard: 130}
7: {date: "2021-04-18", earlyBird: 100, standard: 130}
8: {date: "2021-04-20", earlyBird: 100, standard: 130}
9: {date: "2021-04-21", earlyBird: 0, standard: 200}
10: {date: "2021-04-23", earlyBird: 0, standard: 200}
11: {date: "2021-04-22", earlyBird: 0, standard: 200}
12: {date: "2021-04-24", earlyBird: 0, standard: 200}
13: {date: "2021-04-25", earlyBird: 0, standard: 200}
14: {date: "2021-04-26", earlyBird: 0, standard: 200}
15: {date: "2021-04-27", earlyBird: 0, standard: 200}
16: {date: "2021-04-28", earlyBird: 0, standard: 200}
17: {date: "2021-04-29", earlyBird: 0, standard: 200}
18: {date: "2021-04-30", earlyBird: 0, standard: 200}
19: {date: "2021-05-02", earlyBird: 0, standard: 200}
20: {date: "2021-05-01", earlyBird: 0, standard: 200}
21: {date: "2021-05-03", earlyBird: 0, standard: 200}
22: {date: "2021-05-04", earlyBird: 0, standard: 200}
23: {date: "2021-05-05", earlyBird: 0, standard: 200}
24: {date: "2021-05-06", earlyBird: 0, standard: 200}
25: {date: "2021-05-07", earlyBird: 0, standard: 200}
26: {date: "2021-05-08", earlyBird: 0, standard: 200}
27: {date: "2021-05-09", earlyBird: 0, standard: 200}
28: {date: "2021-05-10", earlyBird: 0, standard: 200}
length: 29
__proto__: Array(0)