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<template>
<table class="files-list" data-cy-files-list>
<!-- Header -->
<div ref="before" class="files-list__before">
<slot name="before" />
</div>
<!-- Header -->
<thead ref="thead" class="files-list__thead" data-cy-files-list-thead>
<slot name="header" />
</thead>
<!-- Body -->
<tbody :style="tbodyStyle"
class="files-list__tbody"
:class="gridMode ? 'files-list__tbody--grid' : 'files-list__tbody--list'"
data-cy-files-list-tbody>
<component :is="dataComponent"
v-for="({key, item}, i) in renderedItems"
:key="key"
:source="item"
:index="i"
v-bind="extraProps" />
</tbody>
<!-- Footer -->
<tfoot v-show="isReady"
class="files-list__tfoot"
data-cy-files-list-tfoot>
<slot name="footer" />
</tfoot>
</table>
</template>
<script lang="ts">
import type { File, Folder, Node } from '@nextcloud/files'
import { debounce } from 'debounce'
import Vue, { PropType } from 'vue'
import filesListWidthMixin from '../mixins/filesListWidth.ts'
import logger from '../logger.js'
interface RecycledPoolItem {
key: string,
item: Node,
}
export default Vue.extend({
name: 'VirtualList',
mixins: [filesListWidthMixin],
props: {
dataComponent: {
type: [Object, Function],
required: true,
},
dataKey: {
type: String,
required: true,
},
dataSources: {
type: Array as PropType<(File | Folder)[]>,
required: true,
},
extraProps: {
type: Object as PropType<Record<string, unknown>>,
default: () => ({}),
},
scrollToIndex: {
type: Number,
default: 0,
},
gridMode: {
type: Boolean,
default: false,
},
},
data() {
return {
index: this.scrollToIndex,
beforeHeight: 0,
headerHeight: 0,
tableHeight: 0,
resizeObserver: null as ResizeObserver | null,
}
},
computed: {
// Wait for measurements to be done before rendering
isReady() {
return this.tableHeight > 0
},
// Items to render before and after the visible area
bufferItems() {
if (this.gridMode) {
return this.columnCount
}
return 3
},
itemHeight() {
// Align with css in FilesListVirtual
// 138px + 44px (name) + 15px (grid gap)
return this.gridMode ? (160 + 44 + 15) : 56
},
// Grid mode only
itemWidth() {
// 160px + 15px grid gap
return 160 + 15
},
rowCount() {
return Math.ceil((this.tableHeight - this.headerHeight) / this.itemHeight) + (this.bufferItems / this.columnCount) * 2 + 1
},
columnCount() {
if (!this.gridMode) {
return 1
}
return Math.floor(this.filesListWidth / this.itemWidth)
},
startIndex() {
return Math.max(0, this.index - this.bufferItems)
},
shownItems() {
// If in grid mode, we need to multiply the number of rows by the number of columns
if (this.gridMode) {
return this.rowCount * this.columnCount
}
return this.rowCount
},
renderedItems(): RecycledPoolItem[] {
if (!this.isReady) {
return []
}
const items = this.dataSources.slice(this.startIndex, this.startIndex + this.shownItems) as Node[]
const oldItems = items.filter(item => Object.values(this.$_recycledPool).includes(item[this.dataKey]))
const oldItemsKeys = oldItems.map(item => item[this.dataKey] as string)
const unusedKeys = Object.keys(this.$_recycledPool).filter(key => !oldItemsKeys.includes(this.$_recycledPool[key]))
return items.map(item => {
const index = Object.values(this.$_recycledPool).indexOf(item[this.dataKey])
// If defined, let's keep the key
if (index !== -1) {
return {
key: Object.keys(this.$_recycledPool)[index],
item,
}
}
// Get and consume reusable key or generate a new one
const key = unusedKeys.pop() || Math.random().toString(36).substr(2)
this.$_recycledPool[key] = item[this.dataKey]
return { key, item }
})
},
tbodyStyle() {
const isOverScrolled = this.startIndex + this.rowCount > this.dataSources.length
const lastIndex = this.dataSources.length - this.startIndex - this.shownItems
const hiddenAfterItems = Math.floor(Math.min(this.dataSources.length - this.startIndex, lastIndex) / this.columnCount)
return {
paddingTop: `${Math.floor(this.startIndex / this.columnCount) * this.itemHeight}px`,
paddingBottom: isOverScrolled ? 0 : `${hiddenAfterItems * this.itemHeight}px`,
}
},
},
watch: {
scrollToIndex(index) {
this.scrollTo(index)
},
columnCount(columnCount, oldColumnCount) {
if (oldColumnCount === 0) {
// We're initializing, the scroll position
// is handled on mounted
console.debug('VirtualList: columnCount is 0, skipping scroll')
return
}
// If the column count changes in grid view,
// update the scroll position again
this.scrollTo(this.index)
},
},
mounted() {
const before = this.$refs?.before as HTMLElement
const root = this.$el as HTMLElement
const thead = this.$refs?.thead as HTMLElement
this.resizeObserver = new ResizeObserver(debounce(() => {
this.beforeHeight = before?.clientHeight ?? 0
this.headerHeight = thead?.clientHeight ?? 0
this.tableHeight = root?.clientHeight ?? 0
logger.debug('VirtualList: resizeObserver updated')
this.onScroll()
}, 100, false))
this.resizeObserver.observe(before)
this.resizeObserver.observe(root)
this.resizeObserver.observe(thead)
if (this.scrollToIndex) {
this.scrollTo(this.scrollToIndex)
}
// Adding scroll listener AFTER the initial scroll to index
this.$el.addEventListener('scroll', this.onScroll, { passive: true })
this.$_recycledPool = {} as Record<string, any>
},
beforeDestroy() {
if (this.resizeObserver) {
this.resizeObserver.disconnect()
}
},
methods: {
scrollTo(index: number) {
this.index = index
// Scroll to one row and a half before the index
const scrollTop = (Math.floor(index / this.columnCount) - 0.5) * this.itemHeight + this.beforeHeight
logger.debug('VirtualList: scrolling to index ' + index, { scrollTop, columnCount: this.columnCount })
this.$el.scrollTop = scrollTop
},
onScroll() {
this._onScrollHandle ??= requestAnimationFrame(() => {
this._onScrollHandle = null;
const topScroll = this.$el.scrollTop - this.beforeHeight
const index = Math.floor(topScroll / this.itemHeight) * this.columnCount
// Max 0 to prevent negative index
this.index = Math.max(0, index)
this.$emit('scroll')
});
},
},
})
</script>
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