feat: virtual scrolling update

Signed-off-by: John Molakvoæ <skjnldsv@protonmail.com>

7 files changed, 690 insertions, 20 deletions

diff --git a/apps/files/src/components/FileEntry.vue b/apps/files/src/components/FileEntry.vue
index c540cc4e824..c271a6965d7 100644
--- a/apps/files/src/components/FileEntry.vue
+++ b/apps/files/src/components/FileEntry.vue
@@ -157,24 +157,24 @@
 <script lang='ts'>
 import { debounce } from 'debounce'
 import { emit } from '@nextcloud/event-bus'
+import { extname } from 'path'
 import { formatFileSize, Permission } from '@nextcloud/files'
 import { Fragment } from 'vue-frag'
-import { extname } from 'path'
+import { generateUrl } from '@nextcloud/router'
 import { showError, showSuccess } from '@nextcloud/dialogs'
 import { translate } from '@nextcloud/l10n'
-import { generateUrl } from '@nextcloud/router'
 import { vOnClickOutside } from '@vueuse/components'
 import axios from '@nextcloud/axios'
 import CancelablePromise from 'cancelable-promise'
 import FileIcon from 'vue-material-design-icons/File.vue'
 import FolderIcon from 'vue-material-design-icons/Folder.vue'
+import moment from '@nextcloud/moment'
 import NcActionButton from '@nextcloud/vue/dist/Components/NcActionButton.js'
 import NcActions from '@nextcloud/vue/dist/Components/NcActions.js'
 import NcCheckboxRadioSwitch from '@nextcloud/vue/dist/Components/NcCheckboxRadioSwitch.js'
 import NcLoadingIcon from '@nextcloud/vue/dist/Components/NcLoadingIcon.js'
 import NcTextField from '@nextcloud/vue/dist/Components/NcTextField.js'
 import Vue from 'vue'
-import type moment from 'moment'
 
 import { ACTION_DETAILS } from '../actions/sidebarAction.ts'
 import { getFileActions, DefaultType } from '../services/FileAction.ts'
@@ -183,9 +183,9 @@ import { isCachedPreview } from '../services/PreviewService.ts'
 import { useActionsMenuStore } from '../store/actionsmenu.ts'
 import { useFilesStore } from '../store/files.ts'
 import { useKeyboardStore } from '../store/keyboard.ts'
+import { useRenamingStore } from '../store/renaming.ts'
 import { useSelectionStore } from '../store/selection.ts'
 import { useUserConfigStore } from '../store/userconfig.ts'
-import { useRenamingStore } from '../store/renaming.ts'
 import CustomElementRender from './CustomElementRender.vue'
 import CustomSvgIconRender from './CustomSvgIconRender.vue'
 import FavoriteIcon from './FavoriteIcon.vue'
@@ -489,21 +489,6 @@ export default Vue.extend({
 	},
 
 	watch: {
-		active(active, before) {
-			if (active === false && before === true) {
-				this.resetState()
-
-				// When the row is not active anymore
-				// remove the display from the row to prevent
-				// keyboard interaction with it.
-				this.$el.parentNode.style.display = 'none'
-				return
-			}
-
-			// Restore default tabindex
-			this.$el.parentNode.style.display = ''
-		},
-
 		/**
 		 * When the source changes, reset the preview
 		 * and fetch the new one.
diff --git a/apps/files/src/components/FilesListFooter.vue b/apps/files/src/components/FilesListFooter.vue
new file mode 100644
index 00000000000..b4a2d7eda30
--- /dev/null
+++ b/apps/files/src/components/FilesListFooter.vue
@@ -0,0 +1,175 @@
+<!--
+  - @copyright Copyright (c) 2023 John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @author John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @license GNU AGPL version 3 or any later version
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program. If not, see <http://www.gnu.org/licenses/>.
+  -
+  -->
+<template>
+	<tr>
+		<th class="files-list__row-checkbox">
+			<span class="hidden-visually">{{ t('files', 'Total rows summary') }}</span>
+		</th>
+
+		<!-- Link to file -->
+		<td class="files-list__row-name">
+			<!-- Icon or preview -->
+			<span class="files-list__row-icon" />
+
+			<!-- Summary -->
+			<span>{{ summary }}</span>
+		</td>
+
+		<!-- Actions -->
+		<td class="files-list__row-actions" />
+
+		<!-- Size -->
+		<td v-if="isSizeAvailable"
+			class="files-list__column files-list__row-size">
+			<span>{{ totalSize }}</span>
+		</td>
+
+		<!-- Mtime -->
+		<td v-if="isMtimeAvailable"
+			class="files-list__column files-list__row-mtime" />
+
+		<!-- Custom views columns -->
+		<th v-for="column in columns"
+			:key="column.id"
+			:class="classForColumn(column)">
+			<span>{{ column.summary?.(nodes, currentView) }}</span>
+		</th>
+	</tr>
+</template>
+
+<script lang="ts">
+import { formatFileSize } from '@nextcloud/files'
+import { translate } from '@nextcloud/l10n'
+import Vue from 'vue'
+
+import { useFilesStore } from '../store/files.ts'
+import { usePathsStore } from '../store/paths.ts'
+
+export default Vue.extend({
+	name: 'FilesListFooter',
+
+	components: {
+	},
+
+	props: {
+		isMtimeAvailable: {
+			type: Boolean,
+			default: false,
+		},
+		isSizeAvailable: {
+			type: Boolean,
+			default: false,
+		},
+		nodes: {
+			type: Array,
+			required: true,
+		},
+		summary: {
+			type: String,
+			default: '',
+		},
+		filesListWidth: {
+			type: Number,
+			default: 0,
+		},
+	},
+
+	setup() {
+		const pathsStore = usePathsStore()
+		const filesStore = useFilesStore()
+		return {
+			filesStore,
+			pathsStore,
+		}
+	},
+
+	computed: {
+		currentView() {
+			return this.$navigation.active
+		},
+
+		dir() {
+			// Remove any trailing slash but leave root slash
+			return (this.$route?.query?.dir || '/').replace(/^(.+)\/$/, '$1')
+		},
+
+		currentFolder() {
+			if (!this.currentView?.id) {
+				return
+			}
+
+			if (this.dir === '/') {
+				return this.filesStore.getRoot(this.currentView.id)
+			}
+			const fileId = this.pathsStore.getPath(this.currentView.id, this.dir)
+			return this.filesStore.getNode(fileId)
+		},
+
+		columns() {
+			// Hide columns if the list is too small
+			if (this.filesListWidth < 512) {
+				return []
+			}
+			return this.currentView?.columns || []
+		},
+
+		totalSize() {
+			// If we have the size already, let's use it
+			if (this.currentFolder?.size) {
+				return formatFileSize(this.currentFolder.size, true)
+			}
+
+			// Otherwise let's compute it
+			return formatFileSize(this.nodes.reduce((total, node) => total + node.size || 0, 0), true)
+		},
+	},
+
+	methods: {
+		classForColumn(column) {
+			return {
+				'files-list__row-column-custom': true,
+				[`files-list__row-${this.currentView.id}-${column.id}`]: true,
+			}
+		},
+
+		t: translate,
+	},
+})
+</script>
+
+<style scoped lang="scss">
+// Scoped row
+tr {
+	padding-bottom: 300px;
+	border-top: 1px solid var(--color-border);
+	// Prevent hover effect on the whole row
+	background-color: transparent !important;
+	border-bottom: none !important;
+}
+
+td {
+	user-select: none;
+	// Make sure the cell colors don't apply to column headers
+	color: var(--color-text-maxcontrast) !important;
+}
+
+</style>
diff --git a/apps/files/src/components/FilesListHeaderActions.vue b/apps/files/src/components/FilesListHeaderActions.vue
new file mode 100644
index 00000000000..e419c8e5abd
--- /dev/null
+++ b/apps/files/src/components/FilesListHeaderActions.vue
@@ -0,0 +1,226 @@
+<!--
+  - @copyright Copyright (c) 2023 John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @author John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @license GNU AGPL version 3 or any later version
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program. If not, see <http://www.gnu.org/licenses/>.
+  -
+  -->
+<template>
+	<th class="files-list__column files-list__row-actions-batch" colspan="2">
+		<NcActions ref="actionsMenu"
+			:disabled="!!loading || areSomeNodesLoading"
+			:force-name="true"
+			:inline="inlineActions"
+			:menu-name="inlineActions <= 1 ? t('files', 'Actions') : null"
+			:open.sync="openedMenu">
+			<NcActionButton v-for="action in enabledActions"
+				:key="action.id"
+				:class="'files-list__row-actions-batch-' + action.id"
+				@click="onActionClick(action)">
+				<template #icon>
+					<NcLoadingIcon v-if="loading === action.id" :size="18" />
+					<CustomSvgIconRender v-else :svg="action.iconSvgInline(nodes, currentView)" />
+				</template>
+				{{ action.displayName(nodes, currentView) }}
+			</NcActionButton>
+		</NcActions>
+	</th>
+</template>
+
+<script lang="ts">
+import { showError, showSuccess } from '@nextcloud/dialogs'
+import { translate } from '@nextcloud/l10n'
+import NcActionButton from '@nextcloud/vue/dist/Components/NcActionButton.js'
+import NcActions from '@nextcloud/vue/dist/Components/NcActions.js'
+import NcLoadingIcon from '@nextcloud/vue/dist/Components/NcLoadingIcon.js'
+import Vue from 'vue'
+
+import { getFileActions } from '../services/FileAction.ts'
+import { useActionsMenuStore } from '../store/actionsmenu.ts'
+import { useFilesStore } from '../store/files.ts'
+import { useSelectionStore } from '../store/selection.ts'
+import filesListWidthMixin from '../mixins/filesListWidth.ts'
+import CustomSvgIconRender from './CustomSvgIconRender.vue'
+import logger from '../logger.js'
+
+// The registered actions list
+const actions = getFileActions()
+
+export default Vue.extend({
+	name: 'FilesListHeaderActions',
+
+	components: {
+		CustomSvgIconRender,
+		NcActions,
+		NcActionButton,
+		NcLoadingIcon,
+	},
+
+	mixins: [
+		filesListWidthMixin,
+	],
+
+	props: {
+		currentView: {
+			type: Object,
+			required: true,
+		},
+		selectedNodes: {
+			type: Array,
+			default: () => ([]),
+		},
+	},
+
+	setup() {
+		const actionsMenuStore = useActionsMenuStore()
+		const filesStore = useFilesStore()
+		const selectionStore = useSelectionStore()
+		return {
+			actionsMenuStore,
+			filesStore,
+			selectionStore,
+		}
+	},
+
+	data() {
+		return {
+			loading: null,
+		}
+	},
+
+	computed: {
+		dir() {
+			// Remove any trailing slash but leave root slash
+			return (this.$route?.query?.dir || '/').replace(/^(.+)\/$/, '$1')
+		},
+		enabledActions() {
+			return actions
+				.filter(action => action.execBatch)
+				.filter(action => !action.enabled || action.enabled(this.nodes, this.currentView))
+				.sort((a, b) => (a.order || 0) - (b.order || 0))
+		},
+
+		nodes() {
+			return this.selectedNodes
+				.map(fileid => this.getNode(fileid))
+				.filter(node => node)
+		},
+
+		areSomeNodesLoading() {
+			return this.nodes.some(node => node._loading)
+		},
+
+		openedMenu: {
+			get() {
+				return this.actionsMenuStore.opened === 'global'
+			},
+			set(opened) {
+				this.actionsMenuStore.opened = opened ? 'global' : null
+			},
+		},
+
+		inlineActions() {
+			if (this.filesListWidth < 512) {
+				return 0
+			}
+			if (this.filesListWidth < 768) {
+				return 1
+			}
+			if (this.filesListWidth < 1024) {
+				return 2
+			}
+			return 3
+		},
+	},
+
+	methods: {
+		/**
+		 * Get a cached note from the store
+		 *
+		 * @param {number} fileId the file id to get
+		 * @return {Folder|File}
+		 */
+		getNode(fileId) {
+			return this.filesStore.getNode(fileId)
+		},
+
+		async onActionClick(action) {
+			const displayName = action.displayName(this.nodes, this.currentView)
+			const selectionIds = this.selectedNodes
+			try {
+				// Set loading markers
+				this.loading = action.id
+				this.nodes.forEach(node => {
+					Vue.set(node, '_loading', true)
+				})
+
+				// Dispatch action execution
+				const results = await action.execBatch(this.nodes, this.currentView, this.dir)
+
+				// Check if all actions returned null
+				if (!results.some(result => result !== null)) {
+					// If the actions returned null, we stay silent
+					this.selectionStore.reset()
+					return
+				}
+
+				// Handle potential failures
+				if (results.some(result => result === false)) {
+					// Remove the failed ids from the selection
+					const failedIds = selectionIds
+						.filter((fileid, index) => results[index] === false)
+					this.selectionStore.set(failedIds)
+
+					showError(this.t('files', '"{displayName}" failed on some elements ', { displayName }))
+					return
+				}
+
+				// Show success message and clear selection
+				showSuccess(this.t('files', '"{displayName}" batch action executed successfully', { displayName }))
+				this.selectionStore.reset()
+			} catch (e) {
+				logger.error('Error while executing action', { action, e })
+				showError(this.t('files', '"{displayName}" action failed', { displayName }))
+			} finally {
+				// Remove loading markers
+				this.loading = null
+				this.nodes.forEach(node => {
+					Vue.set(node, '_loading', false)
+				})
+			}
+		},
+
+		t: translate,
+	},
+})
+</script>
+
+<style scoped lang="scss">
+.files-list__row-actions-batch {
+	flex: 1 1 100% !important;
+
+	// Remove when https://github.com/nextcloud/nextcloud-vue/pull/3936 is merged
+	::v-deep .button-vue__wrapper {
+		width: 100%;
+		span.button-vue__text {
+			overflow: hidden;
+			text-overflow: ellipsis;
+			white-space: nowrap;
+		}
+	}
+}
+</style>
diff --git a/apps/files/src/components/FilesListHeaderButton.vue b/apps/files/src/components/FilesListHeaderButton.vue
new file mode 100644
index 00000000000..9aac83a185d
--- /dev/null
+++ b/apps/files/src/components/FilesListHeaderButton.vue
@@ -0,0 +1,122 @@
+<!--
+  - @copyright Copyright (c) 2023 John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @author John Molakvoæ <skjnldsv@protonmail.com>
+  -
+  - @license GNU AGPL version 3 or any later version
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program. If not, see <http://www.gnu.org/licenses/>.
+  -
+  -->
+<template>
+	<NcButton :aria-label="sortAriaLabel(name)"
+		:class="{'files-list__column-sort-button--active': sortingMode === mode}"
+		class="files-list__column-sort-button"
+		type="tertiary"
+		@click.stop.prevent="toggleSortBy(mode)">
+		<!-- Sort icon before text as size is align right -->
+		<MenuUp v-if="sortingMode !== mode || isAscSorting" slot="icon" />
+		<MenuDown v-else slot="icon" />
+		{{ name }}
+	</NcButton>
+</template>
+
+<script lang="ts">
+import { translate } from '@nextcloud/l10n'
+import MenuDown from 'vue-material-design-icons/MenuDown.vue'
+import MenuUp from 'vue-material-design-icons/MenuUp.vue'
+import NcButton from '@nextcloud/vue/dist/Components/NcButton.js'
+import Vue from 'vue'
+
+import filesSortingMixin from '../mixins/filesSorting.ts'
+
+export default Vue.extend({
+	name: 'FilesListHeaderButton',
+
+	components: {
+		MenuDown,
+		MenuUp,
+		NcButton,
+	},
+
+	mixins: [
+		filesSortingMixin,
+	],
+
+	props: {
+		name: {
+			type: String,
+			required: true,
+		},
+		mode: {
+			type: String,
+			required: true,
+		},
+	},
+
+	methods: {
+		sortAriaLabel(column) {
+			const direction = this.isAscSorting
+				? this.t('files', 'ascending')
+				: this.t('files', 'descending')
+			return this.t('files', 'Sort list by {column} ({direction})', {
+				column,
+				direction,
+			})
+		},
+
+		t: translate,
+	},
+})
+</script>
+
+<style lang="scss">
+.files-list__column-sort-button {
+	// Compensate for cells margin
+	margin: 0 calc(var(--cell-margin) * -1);
+	// Reverse padding
+	padding: 0 4px 0 16px !important;
+
+	// Icon after text
+	.button-vue__wrapper {
+		flex-direction: row-reverse;
+		// Take max inner width for text overflow ellipsis
+		// Remove when https://github.com/nextcloud/nextcloud-vue/pull/3936 is merged
+		width: 100%;
+	}
+
+	.button-vue__icon {
+		transition-timing-function: linear;
+		transition-duration: .1s;
+		transition-property: opacity;
+		opacity: 0;
+	}
+
+	// Remove when https://github.com/nextcloud/nextcloud-vue/pull/3936 is merged
+	.button-vue__text {
+		overflow: hidden;
+		white-space: nowrap;
+		text-overflow: ellipsis;
+	}
+
+	&--active,
+	&:hover,
+	&:focus,
+	&:active {
+		.button-vue__icon {
+			opacity: 1 !important;
+		}
+	}
+}
+</style>
diff --git a/apps/files/src/components/FilesListTableFooter.vue b/apps/files/src/components/FilesListTableFooter.vue
index 4bda140770d..3e8f49deace 100644
--- a/apps/files/src/components/FilesListTableFooter.vue
+++ b/apps/files/src/components/FilesListTableFooter.vue
@@ -20,7 +20,7 @@
   -
   -->
 <template>
-	<tr class="files-list__row-footer">
+	<tr>
 		<th class="files-list__row-checkbox">
 			<span class="hidden-visually">{{ t('files', 'Total rows summary') }}</span>
 		</th>
diff --git a/apps/files/src/components/FilesListVirtual.vue b/apps/files/src/components/FilesListVirtual.vue
index 69cab260963..05de0a38750 100644
--- a/apps/files/src/components/FilesListVirtual.vue
+++ b/apps/files/src/components/FilesListVirtual.vue
@@ -233,6 +233,7 @@ export default Vue.extend({
 			width: 100%;
 			user-select: none;
 			border-bottom: 1px solid var(--color-border);
+			user-select: none;
 		}
 
 		td, th {
diff --git a/apps/files/src/components/VirtualList.vue b/apps/files/src/components/VirtualList.vue
new file mode 100644
index 00000000000..7780665ab6b
--- /dev/null
+++ b/apps/files/src/components/VirtualList.vue
@@ -0,0 +1,161 @@
+<template>
+	<table class="files-list">
+		<!-- Header -->
+		<div ref="before" class="files-list__before">
+			<slot name="before" />
+		</div>
+
+		<!-- Header -->
+		<thead ref="thead" class="files-list__thead">
+			<slot name="header" />
+		</thead>
+
+		<!-- Body -->
+		<tbody :style="tbodyStyle" class="files-list__tbody">
+			<tr v-for="(item, i) in renderedItems"
+				:key="i"
+				:class="{'list__row--active': (i >= bufferItems || index <= bufferItems) && (i < shownItems - bufferItems)}"
+				class="list__row">
+				<component :is="dataComponent"
+					:active="(i >= bufferItems || index <= bufferItems) && (i < shownItems - bufferItems)"
+					:source="item"
+					:index="i"
+					:item-height="itemHeight"
+					v-bind="extraProps" />
+			</tr>
+		</tbody>
+
+		<!-- Footer -->
+		<tfoot ref="tfoot" class="files-list__tfoot">
+			<slot name="footer" />
+		</tfoot>
+	</table>
+</template>
+
+<script lang="ts">
+import { File, Folder } from '@nextcloud/files'
+import { debounce } from 'debounce'
+import Vue from 'vue'
+import logger from '../logger.js'
+
+// 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 as () => (File | Folder)[],
+			required: true,
+		},
+		itemHeight: {
+			type: Number,
+			required: true,
+		},
+		extraProps: {
+			type: Object,
+			default: () => ({}),
+		},
+		scrollToIndex: {
+			type: Number,
+			default: 0,
+		},
+	},
+
+	data() {
+		return {
+			bufferItems,
+			index: this.scrollToIndex,
+			beforeHeight: 0,
+			footerHeight: 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(): (File | Folder)[] {
+			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`,
+			}
+		},
+	},
+	watch: {
+		scrollToIndex() {
+			this.index = this.scrollToIndex
+			this.$el.scrollTop = this.index * this.itemHeight + this.beforeHeight
+		},
+		index() {
+			logger.debug('VirtualList index updated to ' + this.index)
+		},
+	},
+
+	mounted() {
+		const before = this.$refs?.before as HTMLElement
+		const root = this.$el as HTMLElement
+		const tfoot = this.$refs?.tfoot as HTMLElement
+		const thead = this.$refs?.thead as HTMLElement
+
+		this.resizeObserver = new ResizeObserver(debounce(() => {
+			this.beforeHeight = before?.clientHeight ?? 0
+			this.footerHeight = tfoot?.clientHeight ?? 0
+			this.headerHeight = thead?.clientHeight ?? 0
+			this.tableHeight = root?.clientHeight ?? 0
+			logger.debug('VirtualList resizeObserver updated')
+			this.onScroll()
+		}, 100, false))
+
+		this.resizeObserver.observe(before)
+		this.resizeObserver.observe(root)
+		this.resizeObserver.observe(tfoot)
+		this.resizeObserver.observe(thead)
+
+		this.$el.addEventListener('scroll', this.onScroll)
+
+		if (this.scrollToIndex) {
+			this.$el.scrollTop = this.index * this.itemHeight + this.beforeHeight
+		}
+	},
+
+	beforeDestroy() {
+		if (this.resizeObserver) {
+			this.resizeObserver.disconnect()
+		}
+	},
+
+	methods: {
+		onScroll() {
+			// Max 0 to prevent negative index
+			this.index = Math.max(0, Math.round((this.$el.scrollTop - this.beforeHeight) / this.itemHeight))
+		},
+	},
+})
+</script>
+
+<style scoped>
+
+</style>