A RxJS pipeable operator which let the observables to enter into angular zone so that the change detection works properly.

enterZone.ts

import { NgZone } from '@angular/core';
import { Observable } from 'rxjs/Observable';

export function enterZone(zone: NgZone) {
  return <T>(source: Observable<T>) =>
    new Observable<T>(observer =>
      source.subscribe({
        next: (x) => zone.run(() => observer.next(x)),
        error: (err) => observer.error(err),
        complete: () => observer.complete()
    })
   );
}