pinafore/routes/_components/virtualList/VirtualListItem.html
2018-04-19 21:38:01 -07:00

61 lines
1.9 KiB
HTML

<div class="virtual-list-item {{shown ? 'shown' : ''}}"
aria-hidden="{{!shown}}"
virtual-list-key="{{key}}"
ref:node
style="transform: translateY({{offset}}px);" >
<:Component {component}
virtualProps="{{props}}"
virtualIndex="{{index}}"
virtualLength="{{$length}}"
on:recalculateHeight="doRecalculateHeight()"/>
</div>
<style>
.virtual-list-item {
position: absolute;
top: 0;
opacity: 0;
pointer-events: none;
transition: opacity 0.333s linear;
}
.virtual-list-item.shown {
opacity: 1;
pointer-events: auto;
}
</style>
<script>
import { virtualListStore } from './virtualListStore'
import { AsyncLayout } from '../../_utils/AsyncLayout'
import { registerResizeListener, unregisterResizeListener } from '../../_utils/resize'
export default {
oncreate () {
let asyncLayout = new AsyncLayout(node => node.getAttribute('virtual-list-key'))
let { key } = this.get()
asyncLayout.observe(key, this.refs.node, (rect) => {
asyncLayout.disconnect()
// update all item heights in one batch for better perf
this.store.batchUpdateForRealm('itemHeights', key, rect.height)
})
this.doRecalculateHeight = this.doRecalculateHeight.bind(this)
registerResizeListener(this.doRecalculateHeight)
},
ondestroy () {
unregisterResizeListener(this.doRecalculateHeight)
},
store: () => virtualListStore,
computed: {
'shown': ($itemHeights, key) => $itemHeights[key] > 0
},
methods: {
doRecalculateHeight () {
// Recalculate immediately because this is done on-demand, e.g.
// when clicking the "More" button on a spoiler.
let rect = this.refs.node.getBoundingClientRect()
let { key } = this.get()
let { itemHeights } = this.store.get()
itemHeights[key] = rect.height
this.store.setForRealm({itemHeights})
}
}
}
</script>