how do you make multiple http requests using typescript?

You can use mergeMap() and toArray() to make this perform better. ForkJoin would cancel when any of the calls would fail.

submit() {
  const result$ =
  from(this.selectedDate)
  .pipe(
    mergeMap(date => {
      this.booking = {...this.booking, bookDate: date};
      return this.bookingService.create(this.booking);
    }),
    toArray()
  );
}