refactor: pagination/date-separated-list系処理を良い感じに？ (#8209)

* pages/messaging/messaging-room.vue

* wip

* wip

* wip???

* wip?

* :v:

* messaaging-room.form.vue rewrite to compositon api

* refactor

* 関心事でないのでとりあえず置いておく

* :art:

* :art:

* i18n.ts

* fix scroll container find function

* fix

* FIX

* :v:

* Fix scroll bottom detect

* wip

* aaaaaaaaaaa

* rename

* fix

* fix?

* :v:

* :v:

* clean up

* clena up

* refactor

* scroll event once or not

* fix

* fix once

* add safe-area-inset-bottom to spacer

* fix

* :v:

* :art:

* fix

* fix

* wip

* :v:

* clean up

* fix lint

* Update packages/client/src/components/global/sticky-container.vue

Co-authored-by: Johann150 <johann.galle@protonmail.com>

* Update packages/client/src/components/ui/pagination.vue

Co-authored-by: Johann150 <johann.galle@protonmail.com>

* Update packages/client/src/pages/messaging/messaging-room.form.vue

Co-authored-by: Johann150 <johann.galle@protonmail.com>

* clean up: single line comment

* https://github.com/misskey-dev/misskey/pull/8209#discussion_r867386077

* fix

* asobi → tolerance

* pick form

* pick message

* pick room

* fix lint

* fix scroll?

* fix scroll.ts

* fix directives/sticky-container

* update global/sticky-container.vue

* fix, :art:

* revert merge

* :v:

* fix lint errors

* :art:

* Update packages/client/src/types/date-separated-list.ts

Co-authored-by: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

* https://github.com/misskey-dev/misskey/pull/8209#discussion_r917225080

* use '

* Update packages/client/src/scripts/scroll.ts

Co-authored-by: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

* use Number.EPSILON

Co-authored-by: acid-chicken <root@acid-chicken.com>

* revert

* fix

* fix

* Use % instead of vh

* :art:

* :art:

* :art:

* wip

* wip

* css modules

Co-authored-by: Johann150 <johann.galle@protonmail.com>
Co-authored-by: Acid Chicken (硫酸鶏) <root@acid-chicken.com>

3 files changed, 306 insertions, 179 deletions

diff --git a/packages/frontend/src/components/MkDateSeparatedList.vue b/packages/frontend/src/components/MkDateSeparatedList.vue
index 5d8e14c3c8..cb88444d34 100644
--- a/packages/frontend/src/components/MkDateSeparatedList.vue
+++ b/packages/frontend/src/components/MkDateSeparatedList.vue
@@ -1,13 +1,14 @@
 <script lang="ts">
-import { defineComponent, h, PropType, TransitionGroup } from 'vue';
+import { defineComponent, h, PropType, TransitionGroup, useCssModule } from 'vue';
 import MkAd from '@/components/global/MkAd.vue';
 import { i18n } from '@/i18n';
 import { defaultStore } from '@/store';
+import { MisskeyEntity } from '@/types/date-separated-list';
 
 export default defineComponent({
 	props: {
 		items: {
-			type: Array as PropType<{ id: string; createdAt: string; _shouldInsertAd_: boolean; }[]>,
+			type: Array as PropType<MisskeyEntity[]>,
 			required: true,
 		},
 		direction: {
@@ -33,6 +34,7 @@ export default defineComponent({
 	},
 
 	setup(props, { slots, expose }) {
+		const $style = useCssModule();
 		function getDateText(time: string) {
 			const date = new Date(time).getDate();
 			const month = new Date(time).getMonth() + 1;
@@ -57,21 +59,25 @@ export default defineComponent({
 				new Date(item.createdAt).getDate() !== new Date(props.items[i + 1].createdAt).getDate()
 			) {
 				const separator = h('div', {
-					class: 'separator',
+					class: $style['separator'],
 					key: item.id + ':separator',
 				}, h('p', {
-					class: 'date',
+					class: $style['date'],
 				}, [
-					h('span', [
+					h('span', {
+						class: $style['date-1'],
+					}, [
 						h('i', {
-							class: 'ti ti-chevron-up icon',
+							class: `ti ti-chevron-up ${$style['date-1-icon']}`,
 						}),
 						getDateText(item.createdAt),
 					]),
-					h('span', [
+					h('span', {
+						class: $style['date-2'],
+					}, [
 						getDateText(props.items[i + 1].createdAt),
 						h('i', {
-							class: 'ti ti-chevron-down icon',
+							class: `ti ti-chevron-down ${$style['date-2-icon']}`,
 						}),
 					]),
 				]));
@@ -89,100 +95,138 @@ export default defineComponent({
 			}
 		});
 
+		function onBeforeLeave(el: HTMLElement) {
+			el.style.top = `${el.offsetTop}px`;
+			el.style.left = `${el.offsetLeft}px`;
+		}
+		function onLeaveCanceled(el: HTMLElement) {
+			el.style.top = '';
+			el.style.left = '';
+		}
+
 		return () => h(
 			defaultStore.state.animation ? TransitionGroup : 'div',
-			defaultStore.state.animation ? {
-				class: 'sqadhkmv' + (props.noGap ? ' noGap' : ''),
-				name: 'list',
-				tag: 'div',
-				'data-direction': props.direction,
-				'data-reversed': props.reversed ? 'true' : 'false',
-			} : {
-				class: 'sqadhkmv' + (props.noGap ? ' noGap' : ''),
+			{
+					class: {
+						[$style['date-separated-list']]: true,
+						[$style['date-separated-list-nogap']]: props.noGap,
+						[$style['reversed']]: props.reversed,
+						[$style['direction-down']]: props.direction === 'down',
+						[$style['direction-up']]: props.direction === 'up',
+					},
+					...(defaultStore.state.animation ? {
+						name: 'list',
+						tag: 'div',
+						onBeforeLeave,
+						onLeaveCanceled,
+					} : {}),
 			},
 			{ default: renderChildren });
 	},
 });
 </script>
 
-<style lang="scss">
-.sqadhkmv {
+<style lang="scss" module>
+.date-separated-list {
 	container-type: inline-size;
 
-	> *:empty {
-		display: none;
+	&:global {
+	> .list-move {
+		transition: transform 0.7s cubic-bezier(0.23, 1, 0.32, 1);
 	}
 
-	> *:not(:last-child) {
-		margin-bottom: var(--margin);
+	&.deny-move-transition > .list-move {
+		transition: none !important;
 	}
 
-	> .list-move {
-		transition: transform 0.7s cubic-bezier(0.23, 1, 0.32, 1);
+	> .list-leave-active,
+	> .list-enter-active {
+		transition: transform 0.7s cubic-bezier(0.23, 1, 0.32, 1), opacity 0.7s cubic-bezier(0.23, 1, 0.32, 1);
 	}
 
-	> .list-enter-active {
+	> .list-leave-from,
+	> .list-leave-to,
+	> .list-leave-active {
 		transition: transform 0.7s cubic-bezier(0.23, 1, 0.32, 1), opacity 0.7s cubic-bezier(0.23, 1, 0.32, 1);
+		position: absolute !important;
 	}
 
-	&[data-direction="up"] {
-		> .list-enter-from {
-			opacity: 0;
-			transform: translateY(64px);
-		}
+	> *:empty {
+		display: none;
 	}
 
-	&[data-direction="down"] {
-		> .list-enter-from {
-			opacity: 0;
-			transform: translateY(-64px);
+	> *:not(:last-child) {
+		margin-bottom: var(--margin);
+	}
+	}
+}
+
+.date-separated-list-nogap {
+	> * {
+		margin: 0 !important;
+		border: none;
+		border-radius: 0;
+		box-shadow: none;
+
+		&:not(:last-child) {
+			border-bottom: solid 0.5px var(--divider);
 		}
 	}
+}
 
-	> .separator {
-		text-align: center;
+.direction-up {
+	&:global {
+	> .list-enter-from,
+	> .list-leave-to {
+		opacity: 0;
+		transform: translateY(64px);
+	}
+	}
+}
+.direction-down {
+	&:global {
+	> .list-enter-from,
+	> .list-leave-to {
+		opacity: 0;
+		transform: translateY(-64px);
+	}
+	}
+}
 
-		> .date {
-			display: inline-block;
-			position: relative;
-			margin: 0;
-			padding: 0 16px;
-			line-height: 32px;
-			text-align: center;
-			font-size: 12px;
-			color: var(--dateLabelFg);
+.reversed {
+	display: flex;
+	flex-direction: column-reverse;
+}
 
-			> span {
-				&:first-child {
-					margin-right: 8px;
+.separator {
+	text-align: center;
+}
 
-					> .icon {
-						margin-right: 8px;
-					}
-				}
+.date {
+	display: inline-block;
+	position: relative;
+	margin: 0;
+	padding: 0 16px;
+	line-height: 32px;
+	text-align: center;
+	font-size: 12px;
+	color: var(--dateLabelFg);
+}
 
-				&:last-child {
-					margin-left: 8px;
+.date-1 {
+	margin-right: 8px;
+}
 
-					> .icon {
-						margin-left: 8px;
-					}
-				}
-			}
-		}
-	}
+.date-1-icon {
+	margin-right: 8px;
+}
 
-	&.noGap {
-		> * {
-			margin: 0 !important;
-			border: none;
-			border-radius: 0;
-			box-shadow: none;
+.date-2 {
+	margin-left: 8px;
+}
 
-			&:not(:last-child) {
-				border-bottom: solid 0.5px var(--divider);
-			}
-		}
-	}
+.date-2-icon {
+	margin-left: 8px;
 }
 </style>
+
diff --git a/packages/frontend/src/components/MkNotes.vue b/packages/frontend/src/components/MkNotes.vue
index 73659fd501..f9952e4245 100644
--- a/packages/frontend/src/components/MkNotes.vue
+++ b/packages/frontend/src/components/MkNotes.vue
@@ -9,7 +9,16 @@
 
 	<template #default="{ items: notes }">
 		<div :class="[$style.root, { [$style.noGap]: noGap }]">
-			<MkDateSeparatedList ref="notes" v-slot="{ item: note }" :items="notes" :direction="pagination.reversed ? 'up' : 'down'" :reversed="pagination.reversed" :no-gap="noGap" :ad="true" :class="$style.notes">
+			<MkDateSeparatedList
+				ref="notes"
+				v-slot="{ item: note }"
+				:items="notes"
+				:direction="pagination.reversed ? 'up' : 'down'"
+				:reversed="pagination.reversed"
+				:no-gap="noGap"
+				:ad="true"
+				:class="$style.notes"
+			>
 				<XNote :key="note._featuredId_ || note._prId_ || note.id" :class="$style.note" :note="note"/>
 			</MkDateSeparatedList>
 		</div>
diff --git a/packages/frontend/src/components/MkPagination.vue b/packages/frontend/src/components/MkPagination.vue
index b92e6d2360..a78e7e064a 100644
--- a/packages/frontend/src/components/MkPagination.vue
+++ b/packages/frontend/src/components/MkPagination.vue
@@ -15,14 +15,14 @@
 
 	<div v-else ref="rootEl">
 		<div v-show="pagination.reversed && more" key="_more_" class="cxiknjgy _margin">
-			<MkButton v-if="!moreFetching" class="button" :disabled="moreFetching" :style="{ cursor: moreFetching ? 'wait' : 'pointer' }" primary @click="fetchMoreAhead">
+			<MkButton v-if="!moreFetching" v-appear="(enableInfiniteScroll && !props.disableAutoLoad) ? fetchMore : null" class="button" :disabled="moreFetching" :style="{ cursor: moreFetching ? 'wait' : 'pointer' }" primary @click="fetchMore">
 				{{ i18n.ts.loadMore }}
 			</MkButton>
 			<MkLoading v-else class="loading"/>
 		</div>
-		<slot :items="items"></slot>
+		<slot :items="items" :fetching="fetching || moreFetching"></slot>
 		<div v-show="!pagination.reversed && more" key="_more_" class="cxiknjgy _margin">
-			<MkButton v-if="!moreFetching" v-appear="($store.state.enableInfiniteScroll && !disableAutoLoad) ? fetchMore : null" class="button" :disabled="moreFetching" :style="{ cursor: moreFetching ? 'wait' : 'pointer' }" primary @click="fetchMore">
+			<MkButton v-if="!moreFetching" v-appear="(enableInfiniteScroll && !props.disableAutoLoad) ? fetchMore : null" class="button" :disabled="moreFetching" :style="{ cursor: moreFetching ? 'wait' : 'pointer' }" primary @click="fetchMore">
 				{{ i18n.ts.loadMore }}
 			</MkButton>
 			<MkLoading v-else class="loading"/>
@@ -31,15 +31,18 @@
 </Transition>
 </template>
 
-<script lang="ts" setup>
-import { computed, ComputedRef, isRef, markRaw, onActivated, onDeactivated, Ref, ref, shallowRef, watch } from 'vue';
+<script lang="ts">
+import { computed, ComputedRef, isRef, nextTick, onActivated, onBeforeUnmount, onDeactivated, onMounted, ref, watch } from 'vue';
 import * as misskey from 'misskey-js';
 import * as os from '@/os';
-import { onScrollTop, isTopVisible, getScrollPosition, getScrollContainer } from '@/scripts/scroll';
+import { onScrollTop, isTopVisible, getBodyScrollHeight, getScrollContainer, onScrollBottom, scrollToBottom, scroll, isBottomVisible } from '@/scripts/scroll';
 import MkButton from '@/components/MkButton.vue';
+import { defaultStore } from '@/store';
+import { MisskeyEntity } from '@/types/date-separated-list';
 import { i18n } from '@/i18n';
 
 const SECOND_FETCH_LIMIT = 30;
+const TOLERANCE = 16;
 
 export type Paging<E extends keyof misskey.Endpoints = keyof misskey.Endpoints> = {
 	endpoint: E;
@@ -58,8 +61,11 @@ export type Paging<E extends keyof misskey.Endpoints = keyof misskey.Endpoints>
 	reversed?: boolean;
 
 	offsetMode?: boolean;
-};
 
+	pageEl?: HTMLElement;
+};
+</script>
+<script lang="ts" setup>
 const props = withDefaults(defineProps<{
 	pagination: Paging;
 	disableAutoLoad?: boolean;
@@ -72,21 +78,73 @@ const emit = defineEmits<{
 	(ev: 'queue', count: number): void;
 }>();
 
-type Item = { id: string; [another: string]: unknown; };
+let rootEl = $shallowRef<HTMLElement>();
+
+// 遡り中かどうか
+let backed = $ref(false);
+
+let scrollRemove = $ref<(() => void) | null>(null);
 
-const rootEl = shallowRef<HTMLElement>();
-const items = ref<Item[]>([]);
-const queue = ref<Item[]>([]);
+const items = ref<MisskeyEntity[]>([]);
+const queue = ref<MisskeyEntity[]>([]);
 const offset = ref(0);
 const fetching = ref(true);
 const moreFetching = ref(false);
 const more = ref(false);
-const backed = ref(false); // 遡り中か否か
 const isBackTop = ref(false);
 const empty = computed(() => items.value.length === 0);
 const error = ref(false);
+const {
+	enableInfiniteScroll
+} = defaultStore.reactiveState;
 
-const init = async (): Promise<void> => {
+const contentEl = $computed(() => props.pagination.pageEl || rootEl);
+const scrollableElement = $computed(() => getScrollContainer(contentEl));
+
+// 先頭が表示されているかどうかを検出
+// https://qiita.com/mkataigi/items/0154aefd2223ce23398e
+let scrollObserver = $ref<IntersectionObserver>();
+
+watch([() => props.pagination.reversed, $$(scrollableElement)], () => {
+	if (scrollObserver) scrollObserver.disconnect();
+
+	scrollObserver = new IntersectionObserver(entries => {
+		backed = entries[0].isIntersecting;
+	}, {
+		root: scrollableElement,
+		rootMargin: props.pagination.reversed ? '-100% 0px 100% 0px' : '100% 0px -100% 0px',
+		threshold: 0.01,
+	});
+}, { immediate: true });
+
+watch($$(rootEl), () => {
+	scrollObserver.disconnect();
+	nextTick(() => {
+		if (rootEl) scrollObserver.observe(rootEl);
+	});
+});
+
+watch([$$(backed), $$(contentEl)], () => {
+	if (!backed) {
+		if (!contentEl) return;
+
+		scrollRemove = (props.pagination.reversed ? onScrollBottom : onScrollTop)(contentEl, executeQueue, TOLERANCE);
+	} else {
+		if (scrollRemove) scrollRemove();
+		scrollRemove = null;
+	}
+});
+
+if (props.pagination.params && isRef(props.pagination.params)) {
+	watch(props.pagination.params, init, { deep: true });
+}
+
+watch(queue, (a, b) => {
+	if (a.length === 0 && b.length === 0) return;
+	emit('queue', queue.value.length);
+}, { deep: true });
+
+async function init(): Promise<void> {
 	queue.value = [];
 	fetching.value = true;
 	const params = props.pagination.params ? isRef(props.pagination.params) ? props.pagination.params.value : props.pagination.params : {};
@@ -96,18 +154,15 @@ const init = async (): Promise<void> => {
 	}).then(res => {
 		for (let i = 0; i < res.length; i++) {
 			const item = res[i];
-			if (props.pagination.reversed) {
-				if (i === res.length - 2) item._shouldInsertAd_ = true;
-			} else {
-				if (i === 3) item._shouldInsertAd_ = true;
-			}
+			if (i === 3) item._shouldInsertAd_ = true;
 		}
 		if (!props.pagination.noPaging && (res.length > (props.pagination.limit || 10))) {
 			res.pop();
-			items.value = props.pagination.reversed ? [...res].reverse() : res;
+			if (props.pagination.reversed) moreFetching.value = true;
+			items.value = res;
 			more.value = true;
 		} else {
-			items.value = props.pagination.reversed ? [...res].reverse() : res;
+			items.value = res;
 			more.value = false;
 		}
 		offset.value = res.length;
@@ -117,17 +172,16 @@ const init = async (): Promise<void> => {
 		error.value = true;
 		fetching.value = false;
 	});
-};
+}
 
-const reload = (): void => {
+const reload = (): Promise<void> => {
 	items.value = [];
-	init();
+	return init();
 };
 
 const fetchMore = async (): Promise<void> => {
 	if (!more.value || fetching.value || moreFetching.value || items.value.length === 0) return;
 	moreFetching.value = true;
-	backed.value = true;
 	const params = props.pagination.params ? isRef(props.pagination.params) ? props.pagination.params.value : props.pagination.params : {};
 	await os.api(props.pagination.endpoint, {
 		...params,
@@ -142,22 +196,52 @@ const fetchMore = async (): Promise<void> => {
 	}).then(res => {
 		for (let i = 0; i < res.length; i++) {
 			const item = res[i];
-			if (props.pagination.reversed) {
-				if (i === res.length - 9) item._shouldInsertAd_ = true;
-			} else {
-				if (i === 10) item._shouldInsertAd_ = true;
-			}
+			if (i === 10) item._shouldInsertAd_ = true;
 		}
+
+		const reverseConcat = _res => {
+			const oldHeight = scrollableElement ? scrollableElement.scrollHeight : getBodyScrollHeight();
+			const oldScroll = scrollableElement ? scrollableElement.scrollTop : window.scrollY;
+
+			items.value = items.value.concat(_res);
+
+			return nextTick(() => {
+				if (scrollableElement) {
+					scroll(scrollableElement, { top: oldScroll + (scrollableElement.scrollHeight - oldHeight), behavior: 'instant' });
+				} else {
+					window.scroll({ top: oldScroll + (getBodyScrollHeight() - oldHeight), behavior: 'instant' });
+				}
+
+				return nextTick();
+			});
+		};
+
 		if (res.length > SECOND_FETCH_LIMIT) {
 			res.pop();
-			items.value = props.pagination.reversed ? [...res].reverse().concat(items.value) : items.value.concat(res);
-			more.value = true;
+
+			if (props.pagination.reversed) {
+				reverseConcat(res).then(() => {
+					more.value = true;
+					moreFetching.value = false;
+				});
+			} else {
+				items.value = items.value.concat(res);
+				more.value = true;
+				moreFetching.value = false;
+			}
 		} else {
-			items.value = props.pagination.reversed ? [...res].reverse().concat(items.value) : items.value.concat(res);
-			more.value = false;
+			if (props.pagination.reversed) {
+				reverseConcat(res).then(() => {
+					more.value = false;
+					moreFetching.value = false;
+				});
+			} else {
+				items.value = items.value.concat(res);
+				more.value = false;
+				moreFetching.value = false;
+			}
 		}
 		offset.value += res.length;
-		moreFetching.value = false;
 	}, err => {
 		moreFetching.value = false;
 	});
@@ -180,10 +264,10 @@ const fetchMoreAhead = async (): Promise<void> => {
 	}).then(res => {
 		if (res.length > SECOND_FETCH_LIMIT) {
 			res.pop();
-			items.value = props.pagination.reversed ? [...res].reverse().concat(items.value) : items.value.concat(res);
+			items.value = items.value.concat(res);
 			more.value = true;
 		} else {
-			items.value = props.pagination.reversed ? [...res].reverse().concat(items.value) : items.value.concat(res);
+			items.value = items.value.concat(res);
 			more.value = false;
 		}
 		offset.value += res.length;
@@ -193,106 +277,96 @@ const fetchMoreAhead = async (): Promise<void> => {
 	});
 };
 
-const prepend = (item: Item): void => {
-	if (props.pagination.reversed) {
-		if (rootEl.value) {
-			const container = getScrollContainer(rootEl.value);
-			if (container == null) {
-				// TODO?
-			} else {
-				const pos = getScrollPosition(rootEl.value);
-				const viewHeight = container.clientHeight;
-				const height = container.scrollHeight;
-				const isBottom = (pos + viewHeight > height - 32);
-				if (isBottom) {
-					// オーバーフローしたら古いアイテムは捨てる
-					if (items.value.length >= props.displayLimit) {
-						// このやり方だとVue 3.2以降アニメーションが動かなくなる
-						//items.value = items.value.slice(-props.displayLimit);
-						while (items.value.length >= props.displayLimit) {
-							items.value.shift();
-						}
-						more.value = true;
-					}
-				}
-			}
-		}
-		items.value.push(item);
-		// TODO
-	} else {
-		// 初回表示時はunshiftだけでOK
-		if (!rootEl.value) {
-			items.value.unshift(item);
-			return;
-		}
+const prepend = (item: MisskeyEntity): void => {
+	// 初回表示時はunshiftだけでOK
+	if (!rootEl) {
+		items.value.unshift(item);
+		return;
+	}
 
-		const isTop = isBackTop.value || (document.body.contains(rootEl.value) && isTopVisible(rootEl.value));
+	const isTop = isBackTop.value || (props.pagination.reversed ? isBottomVisible : isTopVisible)(contentEl, TOLERANCE);
 
-		if (isTop) {
-			// Prepend the item
-			items.value.unshift(item);
+	if (isTop) unshiftItems([item]);
+	else prependQueue(item);
+};
 
-			// オーバーフローしたら古いアイテムは捨てる
-			if (items.value.length >= props.displayLimit) {
-				// このやり方だとVue 3.2以降アニメーションが動かなくなる
-				//this.items = items.value.slice(0, props.displayLimit);
-				while (items.value.length >= props.displayLimit) {
-					items.value.pop();
-				}
-				more.value = true;
-			}
-		} else {
-			queue.value.push(item);
-			onScrollTop(rootEl.value, () => {
-				for (const item of queue.value) {
-					prepend(item);
-				}
-				queue.value = [];
-			});
-		}
+function unshiftItems(newItems: MisskeyEntity[]) {
+	const length = newItems.length + items.value.length;
+	items.value = [ ...newItems, ...items.value ].slice(0, props.displayLimit);
+
+	if (length >= props.displayLimit) more.value = true;
+}
+
+function executeQueue() {
+	if (queue.value.length === 0) return;
+	unshiftItems(queue.value);
+	queue.value = [];
+}
+
+function prependQueue(newItem: MisskeyEntity) {
+	queue.value.unshift(newItem);
+	if (queue.value.length >= props.displayLimit) {
+		queue.value.pop();
 	}
-};
+}
 
-const append = (item: Item): void => {
+const appendItem = (item: MisskeyEntity): void => {
 	items.value.push(item);
 };
 
-const removeItem = (finder: (item: Item) => boolean) => {
+const removeItem = (finder: (item: MisskeyEntity) => boolean) => {
 	const i = items.value.findIndex(finder);
 	items.value.splice(i, 1);
 };
 
-const updateItem = (id: Item['id'], replacer: (old: Item) => Item): void => {
+const updateItem = (id: MisskeyEntity['id'], replacer: (old: MisskeyEntity) => MisskeyEntity): void => {
 	const i = items.value.findIndex(item => item.id === id);
 	items.value[i] = replacer(items.value[i]);
 };
 
-if (props.pagination.params && isRef(props.pagination.params)) {
-	watch(props.pagination.params, init, { deep: true });
-}
-
-watch(queue, (a, b) => {
-	if (a.length === 0 && b.length === 0) return;
-	emit('queue', queue.value.length);
-}, { deep: true });
-
-init();
+const inited = init();
 
 onActivated(() => {
 	isBackTop.value = false;
 });
 
 onDeactivated(() => {
-	isBackTop.value = window.scrollY === 0;
+	isBackTop.value = props.pagination.reversed ? window.scrollY >= (rootEl ? rootEl?.scrollHeight - window.innerHeight : 0) : window.scrollY === 0;
+});
+
+function toBottom() {
+	scrollToBottom(contentEl);
+}
+
+onMounted(() => {
+	inited.then(() => {
+		if (props.pagination.reversed) {
+			nextTick(() => {
+				setTimeout(toBottom, 800);
+
+				// scrollToBottomでmoreFetchingボタンが画面外まで出るまで
+				// more = trueを遅らせる
+				setTimeout(() => {
+					moreFetching.value = false;
+				}, 2000);
+			});
+		}
+	});
+});
+
+onBeforeUnmount(() => {
+	scrollObserver.disconnect();
 });
 
 defineExpose({
 	items,
 	queue,
 	backed,
+	more,
+	inited,
 	reload,
 	prepend,
-	append,
+	append: appendItem,
 	removeItem,
 	updateItem,
 });