На основе позиции прокрутки и получения атрибута данных JavaScript
<div class="imageWrap"(scroll) = "onScroll($event,imageEl)">
<ul>
<li #imageEl * ngFor="let data of images; let i = index"
[attr.data-image-id] = "image.id" >
<div><img src ="{{data.img}}" width = "500" height = "600" /> </div>
</li>
</ul>
</div>
@HostListener('scroll', ['$event'])
onScroll(event: any, indexI ?) {
let els = document.getElementsByTagName("li");
let offsetHeight = event.target['offsetHeight'];
let scrollTop = event.target['scrollTop'];
let scrollHeight = event.target['scrollHeight'];
this.getImageById(id);
}
getImageById(id){
this.apiService.getimageData(id).subscribe(images => this.images = images);
}
Cloudy Chimpanzee