scrollout js angular
//Install via npm
$ npm i scroll-out -S
//in your component.ts
import ScrollOut from 'scroll-out';
@Component(/**/)
export class MyComponent implements AfterContentInit, OnDestroy {
  so: any;
  constructor(private el: ElementRef) {}
  ngAfterContentInit() {
    this.so = ScrollOut({
      scope: this.el.nativeElement
    });
  }
  ngOnDestroy() {
    this.so.teardown();
  }
}
//In your component.css
[data-scroll] {
  transition: opacity 1s;
}
[data-scroll="in"] {
  opacity: 1;
}
[data-scroll="out"] {
  opacity: 0;
}
//In your component.html
<div data-scroll>Watch me fading in!</div>