Method observe

src/cdk/observers/observe-content.ts:98–119

(elementOrRef: Element | ElementRef<Element>)

  observe(element: ElementRef<Element>): Observable<MutationRecord[]>;

  observe(elementOrRef: Element | ElementRef<Element>): Observable<MutationRecord[]> {
    const element = coerceElement(elementOrRef);

    return new Observable((observer: Observer<MutationRecord[]>) => {
      const stream = this._observeElement(element);
      const subscription = stream
        .pipe(
          map(records => records.filter(record => !shouldIgnoreRecord(record))),
          filter(records => !!records.length),
        )
        .subscribe(records => {
          this._ngZone.run(() => {
            observer.next(records);
          });
        });

      return () => {
        subscription.unsubscribe();
        this._unobserveElement(element);
      };
    });
  }

  /**
   * Observes the given element by using the existing MutationObserver if available, or creating a