Плавающее меню

@HostListener("window:scroll", ['$event']) onScroll(){
   if (this.contentBlock.nativeElement.getBoundingClientRect().top < 0 && window.scrollY < y){
     this.element = document.elementFromPoint(500, 0);
     this.elementId = this.element.id;
     console.log(this.element.id);
 
     this.renderer.addClass(this.menuBlock.nativeElement, 'fixed');
 
     var e = document.getElementById("cont");
    var y = e.scrollHeight;
    
    }
    else{
      this.element = null;
      this.elementId = 'start';
      this.renderer.removeClass(this.menuBlock.nativeElement, 'fixed');
    
    }
    if(this.contentBlock.nativeElement.getBoundingClientRect().top < 0 && window.scrollY > y){
      this.element = document.elementFromPoint(500, 0);
      this.elementId = this.element.id;
      
      this.renderer.addClass(this.menuBlock.nativeElement, 'stop');
 
    }
    else{
      this.renderer.removeClass(this.menuBlock.nativeElement, 'stop');
    }
 
  };

var b: any = document.getElementsByTagName('body');
      var foot: any = document.getElementsByTagName('footer');
      var cont: number = b[0].clientHeight - foot[0].clientHeight;
      console.log('content heigth: ', cont);

@HostListener("window:scroll", ['$event']) onScroll(){
    if (this.contentBlock.nativeElement.getBoundingClientRect().top < 0){
 
      if(!this.isSetPositionFixed){
        this.renderer.removeClass(this.menuBlock.nativeElement, 'fixed');
        this.renderer.addClass(this.menuBlock.nativeElement, 'stop');
      }
      else{
        this.renderer.addClass(this.menuBlock.nativeElement, 'fixed');
        this.renderer.removeClass(this.menuBlock.nativeElement, 'stop');
      }
      
      this.element = document.elementFromPoint(500, 0);
      this.elementId = this.element.id;
 
      // Высота блока меню
      this.menuBlockHeight = this.menuBlock.nativeElement.offsetHeight;
      // Высота блока контента
      this.contentBlockHeight = this.contentBlock.nativeElement.offsetHeight;
 
      this.checkAntiFixed = (this.contentBlock.nativeElement.getBoundingClientRect().top + this.contentBlockHeight - this.menuBlockHeight) < 0;
      this.isSetPositionFixed = !this.checkAntiFixed;
 
      
      console.log('check: ', this.checkAntiFixed);
      console.log('ContentTop: ', this.contentBlock.nativeElement.getBoundingClientRect().top + this.contentBlockHeight - this.menuBlockHeight);
      
      this.element = document.elementFromPoint(500, 0);
      this.elementId = this.element.id;
    }
 
    else{
      this.element = null;
      this.elementId = 'start';
      this.renderer.removeClass(this.menuBlock.nativeElement, 'fixed');
    }
    
  };

export class HowToRentPageComponent implements AfterViewInit {
  element: any = null;
  elementId: string = 'start';
  menuBlockHeight: number = 0;
  contentBlockHeight: number = 0;
  footerBlockHeight: number = 0;
  checkAntiFixed: boolean;
  isSetPositionFixed: boolean;

scrollToElement(val: string){
    var el = document.getElementById(val);
    var coord = el.offsetTop;
    // window.scrollTo(0, coord);
    window.scrollTo({
      top: coord,
      left: 0,
      behavior: "smooth"
    });
  }