Angular 监听滚动条事件

import { fromEvent } from 'rxjs';

this.subscribeScoll = fromEvent(window, 'scroll')
      .subscribe((event) => {
        this.onWindowScroll();
});
onWindowScroll(){console.log(页面滚动了);}；

import { Component, OnInit } from '@angular/core';
import { fromEvent } from 'rxjs'; //引入

@Component({
  selector: 'app-heroes',
  templateUrl: './heroes.component.html',
  styleUrls: ['./heroes.component.css']
})
export class HeroesComponent implements OnInit {
  subscribeScoll:any;
  scrollDis:any = {
    _top:0
  }
  constructor() { }
  ngOnInit() {
    this.subscribeScoll = fromEvent(window, 'scroll')
      .subscribe((event) => {
        this.onWindowScroll();//调用
    });
  }
  scollPostion() {
    var t, l, w, h;
    if (document.documentElement && document.documentElement.scrollTop) {
        t = document.documentElement.scrollTop;
        l = document.documentElement.scrollLeft;
        w = document.documentElement.scrollWidth;
        h = document.documentElement.scrollHeight;
    } else if (document.body) {
        t = document.body.scrollTop;
        l = document.body.scrollLeft;
        w = document.body.scrollWidth;
        h = document.body.scrollHeight;
    }
    return {
        top: t,
        left: l,
        width: w,
        height: h
    };
  }
  onWindowScroll(){
    this.scrollDis._top = this.scollPostion().top;
    console.log(this.scrollDis._top);
  }
}