semaphore/routes/_components/Timeline.html

<div class="timeline">
  <VirtualList component="{{StatusListItem}}"
               items="{{keyedStatuses}}"
               on:scrollToBottom="onScrollToBottom()" />
</div>
<style>
  .timeline {
    min-height: 50vh;
  }
</style>
<script>
  import { store } from '../_utils/store'
  import { getHomeTimeline } from '../_utils/mastodon/oauth'
  import StatusListItem from './StatusListItem.html'
  import VirtualList from './VirtualList.html'
  import { splice, push } from 'svelte-extras'
  import { mark, stop } from '../_utils/marks'

  export default {
    async oncreate() {
      let instanceName = this.store.get('currentInstance')
      let instanceData = this.store.get('currentInstanceData')
      let statuses = await getHomeTimeline(instanceName, instanceData.access_token, null, 10)
      this.set({
        statuses: statuses,
      })
    },
    data: () => ({
      target: 'home',
      StatusListItem: StatusListItem,
      statuses: [],
      runningUpdate: false
    }),
    computed: {
      keyedStatuses: (statuses) => statuses.map(status => ({
        props: status,
        key: status.id
      })),
      lastStatusId: (statuses) => statuses.length && statuses[statuses.length - 1].id
    },
    store: () => store,
    components: {
      VirtualList
    },
    methods: {
      splice: splice,
      push: push,
      async onScrollToBottom() {
        mark('onScrollToBottom')
        if (this.get('runningUpdate')) {
          return
        }
        this.set({ runningUpdate: true })
        let lastStatusId = this.get('lastStatusId')
        let instanceName = this.store.get('currentInstance')
        let instanceData = this.store.get('currentInstanceData')
        let newStatuses = await getHomeTimeline(instanceName, instanceData.access_token, lastStatusId, 10)
        let statuses = this.get('statuses')
        if (statuses) {
          this.addItems(newStatuses)
        }
        this.set({ runningUpdate: false })
        stop('onScrollToBottom')
      },
      addItems(items) {
        this.splice('statuses', this.get('statuses').length, 0, ...items)
      }
    }
  }
</script>