medium-rxjs-multicast-take.ts

function takeWhileInclusive<T>(
  predicate: (value: T) => boolean
): (source: Observable<T>) => Observable<T> {

  return source => source.multicast(
    () => new ReplaySubject<T>(1),
    shared => shared
      .takeWhile(predicate)
      .concat(shared.take(1).filter(t => !predicate(t)))
  );
}