From dbc98cdc4e15b4f5f746c867c52a0fc145d214d0 Mon Sep 17 00:00:00 2001
From: pa <maplenagisa@gmail.com>
Date: Sun, 25 Jan 2026 20:43:04 +0900
Subject: [PATCH] fix @tanstack/virtual not fully support smooth scroll
 behavior on dynamic height containers

---
 src/components/BackToTop.vue                  |  84 ++++++---
 src/components/BackToTopVirtual.vue           | 161 ------------------
 .../Sidebar/components/FriendsSidebar.vue     |   4 +-
 .../Sidebar/components/GroupsSidebar.vue      |   4 +-
 4 files changed, 65 insertions(+), 188 deletions(-)
 delete mode 100644 src/components/BackToTopVirtual.vue

diff --git a/src/components/BackToTop.vue b/src/components/BackToTop.vue
index 54403c35..926821d0 100644
--- a/src/components/BackToTop.vue
+++ b/src/components/BackToTop.vue
@@ -5,12 +5,15 @@
     import { Button } from '@/components/ui/button';
 
     const props = defineProps({
+        // scroll DOM ref
         target: { type: [String, Object], default: null },
+        // @tanstack/virtual instance
+        virtualizer: { type: [Object], default: null },
 
         bottom: { type: Number, default: 20 },
         right: { type: Number, default: 20 },
 
-        visibilityHeight: { type: Number, default: 200 },
+        visibilityHeight: { type: Number, default: 400 },
 
         behavior: {
             type: String,
@@ -21,28 +24,26 @@
         tooltip: { type: Boolean, default: true },
         tooltipText: { type: String, default: 'Back to top' },
 
-        teleport: { type: Boolean, default: true }
+        teleport: { type: Boolean, default: true },
+        teleportTo: { type: [Boolean, String, Object], default: null }
     });
 
     const visible = ref(false);
     let containerEl = null;
 
-    function resolveTarget() {
-        if (!props.target) return null;
-        if (typeof props.target === 'string') {
-            return document.querySelector(props.target);
+    function resolveElement(target) {
+        if (!target) return null;
+        if (typeof target === 'string') return document.querySelector(target);
+        if (typeof target === 'object') {
+            if ('value' in target) return target.value;
+            if ('$el' in target) return target.$el;
         }
+        return target;
+    }
 
-        if (typeof props.target === 'object') {
-            if ('value' in props.target) {
-                return props.target.value;
-            }
-            if ('$el' in props.target) {
-                return props.target.$el;
-            }
-        }
-
-        return props.target;
+    function getVirtualizer() {
+        if (!props.virtualizer) return null;
+        return 'value' in props.virtualizer ? props.virtualizer.value : props.virtualizer;
     }
 
     function getScrollTop() {
@@ -58,15 +59,21 @@
 
     function scrollToTop() {
         const behavior = props.behavior === 'auto' ? 'auto' : 'smooth';
-        if (!containerEl || typeof containerEl.scrollTo !== 'function') {
-            window.scrollTo({ top: 0, behavior });
+        const v = getVirtualizer();
+        if (v?.scrollToIndex) {
+            v.scrollToIndex(0, { align: 'start', behavior: 'auto' });
             return;
         }
-        containerEl.scrollTo({ top: 0, behavior });
+        const target = containerEl || resolveElement(props.target);
+        if (target && typeof target.scrollTo === 'function') {
+            target.scrollTo({ top: 0, behavior });
+            return;
+        }
+        window.scrollTo({ top: 0, behavior });
     }
 
     function bind() {
-        containerEl = resolveTarget();
+        containerEl = resolveElement(props.target);
 
         const target = containerEl && typeof containerEl.addEventListener === 'function' ? containerEl : window;
         target.addEventListener('scroll', handleScroll, { passive: true });
@@ -94,13 +101,25 @@
         unbind();
     });
 
+    const teleportTarget = computed(() => {
+        if (props.teleportTo !== null && props.teleportTo !== undefined) {
+            if (props.teleportTo === true) return 'body';
+            if (props.teleportTo === false) return null;
+            return resolveElement(props.teleportTo);
+        }
+        return props.teleport ? 'body' : null;
+    });
+
+    const isBodyTeleport = computed(() => teleportTarget.value === 'body' || teleportTarget.value === document.body);
+
     const wrapperStyle = computed(
-        () => `position:fixed; right:${props.right}px; bottom:${props.bottom}px; z-index:50;`
+        () =>
+            `position:${isBodyTeleport.value ? 'fixed' : 'absolute'}; right:${props.right}px; bottom:${props.bottom}px; z-index:50;`
     );
 </script>
 
 <template>
-    <Teleport v-if="teleport" to="body">
+    <Teleport v-if="teleportTarget" :to="teleportTarget">
         <Transition name="back-to-top">
             <div v-if="visible" :style="wrapperStyle">
                 <TooltipProvider v-if="tooltip">
@@ -115,7 +134,7 @@
                                 <ArrowUp class="h-4 w-4" />
                             </Button>
                         </TooltipTrigger>
-                        <TooltipContent side="left">
+                        <TooltipContent side="top">
                             {{ tooltipText }}
                         </TooltipContent>
                     </Tooltip>
@@ -136,7 +155,26 @@
 
     <Transition v-else name="back-to-top">
         <div v-if="visible" :style="wrapperStyle">
+            <TooltipProvider v-if="tooltip">
+                <Tooltip>
+                    <TooltipTrigger as-child>
+                        <Button
+                            size="icon"
+                            variant="secondary"
+                            class="rounded-full shadow"
+                            aria-label="Back to top"
+                            @click="scrollToTop">
+                            <ArrowUp class="h-4 w-4" />
+                        </Button>
+                    </TooltipTrigger>
+                    <TooltipContent side="top">
+                        {{ tooltipText }}
+                    </TooltipContent>
+                </Tooltip>
+            </TooltipProvider>
+
             <Button
+                v-else
                 size="icon"
                 variant="secondary"
                 class="rounded-full shadow"
diff --git a/src/components/BackToTopVirtual.vue b/src/components/BackToTopVirtual.vue
deleted file mode 100644
index 7817f91b..00000000
--- a/src/components/BackToTopVirtual.vue
+++ /dev/null
@@ -1,161 +0,0 @@
-<script setup>
-    import { computed, onBeforeUnmount, onMounted, ref, watch } from 'vue';
-    import { ArrowUp } from 'lucide-vue-next';
-    import { Button } from '@/components/ui/button';
-
-    const props = defineProps({
-        // scroll DOM ref
-        target: { type: [String, Object], default: null },
-        // @tanstack/virtual instance
-        virtualizer: { type: [Object], default: null },
-
-        bottom: { type: Number, default: 4 },
-        right: { type: Number, default: 10 },
-
-        visibilityHeight: { type: Number, default: 500 },
-
-        behavior: {
-            type: String,
-            default: 'smooth',
-            validator: (value) => value === 'auto' || value === 'smooth'
-        },
-
-        teleportTo: { type: [String, Object], default: null }
-    });
-
-    const visible = ref(false);
-    let containerEl = null;
-
-    function resolveElement(target) {
-        if (!target) return null;
-        if (typeof target === 'string') return document.querySelector(target);
-        if (typeof target === 'object') {
-            if ('value' in target) return target.value;
-            if ('$el' in target) return target.$el;
-        }
-        return target;
-    }
-
-    function getVirtualizer() {
-        if (!props.virtualizer) return null;
-        return 'value' in props.virtualizer ? props.virtualizer.value : props.virtualizer;
-    }
-
-    function getScrollTop() {
-        if (!containerEl || typeof containerEl.scrollTop !== 'number') {
-            return window.scrollY || document.documentElement.scrollTop || 0;
-        }
-        return containerEl.scrollTop || 0;
-    }
-
-    function handleScroll() {
-        visible.value = getScrollTop() >= props.visibilityHeight;
-    }
-
-    function scrollToTop() {
-        const behavior = props.behavior === 'auto' ? 'auto' : 'smooth';
-        const v = getVirtualizer();
-        if (v?.scrollToIndex) {
-            v.scrollToIndex(0, { align: 'start', behavior });
-            return;
-        }
-        const target = containerEl || resolveElement(props.target);
-        if (target && typeof target.scrollTo === 'function') {
-            target.scrollTo({ top: 0, behavior });
-            return;
-        }
-        window.scrollTo({ top: 0, behavior });
-    }
-
-    function bind() {
-        containerEl = resolveElement(props.target);
-        const target = containerEl && typeof containerEl.addEventListener === 'function' ? containerEl : window;
-        target.addEventListener('scroll', handleScroll, { passive: true });
-        handleScroll();
-    }
-
-    function unbind() {
-        const target = containerEl || window;
-        target.removeEventListener('scroll', handleScroll);
-    }
-
-    onMounted(() => {
-        bind();
-    });
-
-    watch(
-        () => props.target,
-        () => {
-            unbind();
-            bind();
-        }
-    );
-
-    onBeforeUnmount(() => {
-        unbind();
-    });
-
-    const wrapperStyle = computed(
-        () => `position:absolute; right:${props.right}px; bottom:${props.bottom}px; z-index:10;`
-    );
-
-    const teleportTarget = computed(() => resolveElement(props.teleportTo));
-</script>
-
-<template>
-    <Teleport v-if="teleportTarget" :to="teleportTarget">
-        <Transition name="back-to-top">
-            <div v-if="visible" :style="wrapperStyle">
-                <Button
-                    size="icon"
-                    variant="secondary"
-                    class="rounded-full shadow"
-                    aria-label="Back to top"
-                    @click="scrollToTop">
-                    <ArrowUp />
-                </Button>
-            </div>
-        </Transition>
-    </Teleport>
-
-    <Transition v-else name="back-to-top">
-        <div v-if="visible" :style="wrapperStyle">
-            <Button
-                size="icon"
-                variant="secondary"
-                class="rounded-full shadow"
-                aria-label="Back to top"
-                @click="scrollToTop">
-                <ArrowUp />
-            </Button>
-        </div>
-    </Transition>
-</template>
-
-<style scoped>
-    .back-to-top-enter-active,
-    .back-to-top-leave-active {
-        transition:
-            opacity 160ms ease,
-            transform 160ms ease;
-    }
-
-    .back-to-top-enter-from,
-    .back-to-top-leave-to {
-        opacity: 0;
-        transform: translateY(6px);
-    }
-
-    .back-to-top-enter-to,
-    .back-to-top-leave-from {
-        opacity: 1;
-        transform: translateY(0);
-    }
-
-    @media (prefers-reduced-motion: reduce) {
-        .back-to-top-enter-active,
-        .back-to-top-leave-active {
-            transition: none;
-        }
-    }
-</style>
diff --git a/src/views/Sidebar/components/FriendsSidebar.vue b/src/views/Sidebar/components/FriendsSidebar.vue
index bd2b2e25..e693a66d 100644
--- a/src/views/Sidebar/components/FriendsSidebar.vue
+++ b/src/views/Sidebar/components/FriendsSidebar.vue
@@ -84,7 +84,7 @@
                 </div>
             </div>
         </div>
-        <BackToTopVirtual :virtualizer="virtualizer" :target="scrollViewportRef" :teleport-to="scrollRootRef" />
+        <BackToTop :virtualizer="virtualizer" :target="scrollViewportRef" :tooltip="false" />
     </div>
 </template>
 
@@ -107,7 +107,7 @@
     import { isRealInstance, userImage, userStatusClass } from '../../../shared/utils';
     import { getFriendsLocations } from '../../../shared/utils/location.js';
 
-    import BackToTopVirtual from '../../../components/BackToTopVirtual.vue';
+    import BackToTop from '../../../components/BackToTop.vue';
     import FriendItem from './FriendItem.vue';
     import Location from '../../../components/Location.vue';
     import configRepository from '../../../service/config';
diff --git a/src/views/Sidebar/components/GroupsSidebar.vue b/src/views/Sidebar/components/GroupsSidebar.vue
index cd3818dc..357ffaa9 100644
--- a/src/views/Sidebar/components/GroupsSidebar.vue
+++ b/src/views/Sidebar/components/GroupsSidebar.vue
@@ -52,7 +52,7 @@
                 </div>
             </div>
         </div>
-        <BackToTopVirtual :virtualizer="virtualizer" :target="scrollViewportRef" :teleport-to="scrollRootRef" />
+        <BackToTop :virtualizer="virtualizer" :target="scrollViewportRef" :tooltip="false" />
     </div>
 </template>
 
@@ -65,7 +65,7 @@
     import { useAppearanceSettingsStore, useGroupStore } from '../../../stores';
     import { convertFileUrlToImageUrl } from '../../../shared/utils';
 
-    import BackToTopVirtual from '../../../components/BackToTopVirtual.vue';
+    import BackToTop from '../../../components/BackToTop.vue';
     import Location from '../../../components/Location.vue';
 
     const { isAgeGatedInstancesVisible } = storeToRefs(useAppearanceSettingsStore());