constructor(private chapterService: ChapterService, private userSevice:ApiService, private route: ActivatedRoute, private ngZone: NgZone) {
    this.route.paramMap.subscribe(params => {
      this.ngOnInit();
  });
    this.chapterNumber = "0";
    this.username=localStorage.getItem("loggedUserUsername")
    //get chapter number save from user
  }

  getChapter(): any {
      const chN = this.route.snapshot.paramMap.get("chNumber");
    if (chN) {
      this.notificationVisible=false;
      return this.chapterService
        .GetChapterByChapterNumber(chN)
        .pipe(
          map(
            (data) => {
              this.chapter = data;

            }))

    }
  }

  ngOnInit(): void {
    this.getChapter().subscribe(() => {
      console.log('ngOnit after getChapter() ' + this.chapter);
    });