pinafore/routes/_components/virtualList/VirtualListContainer.html

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<slot></slot>
<script>
import { virtualListStore } from './virtualListStore'
import throttle from 'lodash-es/throttle'
import { isFullscreen, attachFullscreenListener, detachFullscreenListener } from '../../_utils/fullscreen'
import { mark, stop } from '../../_utils/marks'
import { scheduleIdleTask } from '../../_utils/scheduleIdleTask'
import { isMobile } from '../../_utils/isMobile'
import { doubleRAF } from '../../_utils/doubleRAF'
const SCROLL_EVENT_DELAY = 300
export default {
oncreate () {
mark('onCreate VirtualListContainer')
let {
realm,
containerQuery
} = this.get()
this.store.setCurrentRealm(realm)
let node = document.querySelector(containerQuery)
this.setupScroll(node)
this.setupFullscreen()
let { scrollTop } = this.store.get()
if (scrollTop > 0) {
this.observe('allVisibleItemsHaveHeight', allVisibleItemsHaveHeight => {
console.log('allVisibleItemsHaveHeight', allVisibleItemsHaveHeight)
let { initializedScrollTop } = this.get()
if (!initializedScrollTop && allVisibleItemsHaveHeight && node) {
this.set({'initializedScrollTop': true})
mark('set scrollTop')
console.log('forcing scroll top to ', scrollTop)
node.scrollTop = scrollTop
stop('set scrollTop')
doubleRAF(() => {
console.log('initialized VirtualList')
this.fire('initialized')
})
}
})
} else {
this.fire('noNeedToScroll')
this.observe('allVisibleItemsHaveHeight', allVisibleItemsHaveHeight => {
if (allVisibleItemsHaveHeight) {
console.log('initialized VirtualList')
this.fire('initialized')
}
})
this.store.setForRealm({
scrollHeight: node.scrollHeight,
offsetHeight: node.offsetHeight
})
}
stop('onCreate VirtualListContainer')
},
ondestroy () {
this.teardownScroll()
this.teardownFullscreen()
this.store.setCurrentRealm(null)
},
store: () => virtualListStore,
methods: {
setupScroll (node) {
if (!node) {
return
}
this.scrollListener = throttle(event => {
let { fullscreen } = this.get()
if (fullscreen) {
return
}
this.onScroll(event)
}, SCROLL_EVENT_DELAY, {
leading: true,
trailing: true
})
node.addEventListener('scroll', this.scrollListener)
},
teardownScroll () {
let { containerQuery } = this.get()
let node = document.querySelector(containerQuery)
if (node) {
node.removeEventListener('scroll', this.scrollListener)
}
},
setupFullscreen () {
this.onFullscreenChange = this.onFullscreenChange.bind(this)
attachFullscreenListener(this.onFullscreenChange)
},
teardownFullscreen () {
detachFullscreenListener(this.onFullscreenChange)
},
onScroll (event) {
let { scrollTop, scrollHeight } = event.target
// On mobile devices, this can make scrolling more responsive. On
// desktop browsers... it's probably overkill, and can lead to a
// checkerboarding issue ("I just scrolled, why is it blank for 5 seconds?").
let runTask = isMobile() ? scheduleIdleTask : requestAnimationFrame
runTask(() => {
mark('onScroll -> setForRealm()')
this.store.setForRealm({scrollTop, scrollHeight})
stop('onScroll -> setForRealm()')
})
},
onFullscreenChange () {
mark('onFullscreenChange')
console.log('is fullscreen? ', isFullscreen())
this.set({ fullscreen: isFullscreen() })
stop('onFullscreenChange')
}
},
computed: {
// TODO: bug in svelte/store the observer in oncreate() never get removed without this hack
allVisibleItemsHaveHeight: ($allVisibleItemsHaveHeight) => $allVisibleItemsHaveHeight
}
}
</script>