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<!--
- SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
- SPDX-License-Identifier: AGPL-3.0-or-later
-->
<template>
<table class="user-list">
<slot name="before" />
<thead ref="thead"
role="rowgroup"
class="user-list__header">
<slot name="header" />
</thead>
<tbody :style="tbodyStyle"
class="user-list__body">
<component :is="dataComponent"
v-for="(item, i) in renderedItems"
:key="item[dataKey]"
:user="item"
:visible="(i >= bufferItems || index <= bufferItems) && (i < shownItems - bufferItems)"
v-bind="extraProps" />
</tbody>
<tfoot ref="tfoot"
v-element-visibility="handleFooterVisibility"
role="rowgroup"
class="user-list__footer">
<slot name="footer" />
</tfoot>
</table>
</template>
<script lang="ts">
import Vue from 'vue'
import { vElementVisibility } from '@vueuse/components'
import debounce from 'debounce'
import logger from '../../logger.ts'
Vue.directive('elementVisibility', vElementVisibility)
// Items to render before and after the visible area
const bufferItems = 3
export default Vue.extend({
name: 'VirtualList',
props: {
dataComponent: {
type: [Object, Function],
required: true,
},
dataKey: {
type: String,
required: true,
},
dataSources: {
type: Array,
required: true,
},
itemHeight: {
type: Number,
required: true,
},
extraProps: {
type: Object,
default: () => ({}),
},
},
data() {
return {
bufferItems,
index: 0,
headerHeight: 0,
tableHeight: 0,
resizeObserver: null as ResizeObserver | null,
}
},
computed: {
startIndex() {
return Math.max(0, this.index - bufferItems)
},
shownItems() {
return Math.ceil((this.tableHeight - this.headerHeight) / this.itemHeight) + bufferItems * 2
},
renderedItems() {
return this.dataSources.slice(this.startIndex, this.startIndex + this.shownItems)
},
tbodyStyle() {
const isOverScrolled = this.startIndex + this.shownItems > this.dataSources.length
const lastIndex = this.dataSources.length - this.startIndex - this.shownItems
const hiddenAfterItems = Math.min(this.dataSources.length - this.startIndex, lastIndex)
return {
paddingTop: `${this.startIndex * this.itemHeight}px`,
paddingBottom: isOverScrolled ? 0 : `${hiddenAfterItems * this.itemHeight}px`,
}
},
},
mounted() {
const root = this.$el as HTMLElement
const tfoot = this.$refs?.tfoot as HTMLElement
const thead = this.$refs?.thead as HTMLElement
this.resizeObserver = new ResizeObserver(debounce(() => {
this.headerHeight = thead?.clientHeight ?? 0
this.tableHeight = root?.clientHeight ?? 0
logger.debug('VirtualList resizeObserver updated')
this.onScroll()
}, 100, false))
this.resizeObserver.observe(root)
this.resizeObserver.observe(tfoot)
this.resizeObserver.observe(thead)
this.$el.addEventListener('scroll', this.onScroll)
},
beforeDestroy() {
if (this.resizeObserver) {
this.resizeObserver.disconnect()
}
},
methods: {
handleFooterVisibility(visible: boolean) {
if (visible) {
this.$emit('scroll-end')
}
},
onScroll() {
// Max 0 to prevent negative index
this.index = Math.max(0, Math.round(this.$el.scrollTop / this.itemHeight))
},
},
})
</script>
<style lang="scss" scoped>
.user-list {
--avatar-cell-width: 48px;
--cell-padding: 7px;
--cell-width: 200px;
--cell-width-large: 300px;
--cell-min-width: calc(var(--cell-width) - (2 * var(--cell-padding)));
--sticky-column-z-index: calc(var(--vs-dropdown-z-index) + 1); // Keep the sticky column on top of the select dropdown
// Necessary for virtual scroll optimized rendering
display: block;
overflow: auto;
height: 100%;
will-change: scroll-position;
&__header,
&__footer {
position: sticky;
// Fix sticky positioning in Firefox
display: block;
}
&__header {
top: 0;
z-index: calc(var(--sticky-column-z-index) + 1);
}
&__footer {
inset-inline-start: 0;
}
&__body {
display: flex;
flex-direction: column;
width: 100%;
}
}
</style>
|
