Pinafore-Web-Client-Frontend/routes/_components/VirtualListContainer.html

<div class="container"
     on:scroll="onScroll(event)"
     on:fullscreen="onFullscreenChange()"
     ref:node>
  <slot></slot>
</div>
<script>
  import { getVirtualStore } from '../_utils/virtualStoreCache'
  import throttle from 'lodash/throttle'
  import { isFullscreen, attachFullscreenListener, detachFullscreenListener } from '../_utils/fullscreen'
  import { mark, stop } from '../_utils/marks'
  import { virtualStoreCache } from '../_utils/virtualStoreCache'

  const SCROLL_EVENT_DELAY = 300

  export default {
    oncreate() {
      mark('onCreate VirtualListContainer')
      let node = this.refs.node
      this.store.set({
        scrollTop: node.scrollTop,
        scrollHeight: node.scrollHeight,
        offsetHeight: node.offsetHeight
      })
      stop('onCreate VirtualListContainer')
    },
    store: () => getVirtualStore(this.get('storeKey')),
    events: {
      scroll(node, callback) {
        const onScroll = throttle(event => {
          mark('onScroll')
          if (this.get('fullscreen')) {
            return
          }
          callback(event)
          stop('onScroll')
        }, SCROLL_EVENT_DELAY, {
          leading: true,
          trailing: true
        })
        node.addEventListener('scroll', onScroll)

        return {
          teardown() {
            node.removeEventListener('scroll', onScroll)
          }
        }
      },
      fullscreen(node, callback) {
        const onFullscreen = (() => {
          callback()
        })
        attachFullscreenListener(onFullscreen)
        return {
          teardown() {
            detachFullscreenListener(onFullscreen)
          }
        }
      }
    },
    methods: {
      onScroll(event) {
        this.store.set({
          scrollTop: event.target.scrollTop,
          scrollHeight: event.target.scrollHeight
        })
      },
      onFullscreenChange() {
        mark('onFullscreenChange')
        console.log('is fullscreen? ', isFullscreen())
        this.set({ fullscreen: isFullscreen() })
        stop('onFullscreenChange')
      }
    }
  };
</script>