Add view caching and preserve folder/editor UI state

frontend/src/App.vue

@@ -24,14 +24,21 @@
     />
   </header>
   <main class="transition-wrapper">
+    <RouterView v-slot="{ Component }">
       <Transition
         :name="routeTransitionName"
         @after-enter="store.transitionDirection = 'none'"
       >
-      <div :key="routeViewKey" class="explorer-content">
-        <RouterView :path="path.pathList" :query="path.query" />
-      </div>
+        <KeepAlive>
+          <component
+            :is="Component"
+            :key="routeViewKey"
+            class="explorer-content"
+            v-bind="routeViewProps"
+          />
+        </KeepAlive>
       </Transition>
+    </RouterView>
   </main>
   <footer v-if="store.selected.size || store.uprogress.total || store.dprogress.total">
     <SelectionToolbar :path="path.pathList" />
@@ -103,6 +110,11 @@ const routeViewKey = computed(() => {
   const route = Router.currentRoute.value
   return route.name === 'editor' ? route.path : String(route.name ?? route.path)
 })
+const routeViewProps = computed(() =>
+  path.value.isEditorPath
+    ? {}
+    : { path: path.value.pathList, query: path.value.query }
+)
 watch(
   () => path.value.path,
   () => {

frontend/src/components/Gallery.vue

@@ -23,6 +23,8 @@ import type { SortOrder } from '@/utils/docsort'
 import { createKeyboardFollowScroll } from '@/utils/keyboardFollowScroll'
 import ContextMenu from '@imengyu/vue3-context-menu'
 import {
+  onActivated,
+  onDeactivated,
   computed,
   nextTick,
   onMounted,
@@ -170,6 +172,7 @@ const onImgLoad = (e: Event) => {
 }
 const updateColumns = () => {
   if (!gallery.value) return
+  if (gallery.value.getBoundingClientRect().width <= 0) return
   const style = getComputedStyle(gallery.value)
   const templates = style.gridTemplateColumns
     .split(' ')
@@ -412,6 +415,19 @@ watchEffect(() => {
   }
 })
 let resizeObserver: ResizeObserver | null = null
+const attachGalleryObservers = () => {
+  if (!gallery.value || resizeObserver) return
+  resizeObserver = new ResizeObserver(updateColumns)
+  resizeObserver.observe(gallery.value)
+  gallery.value.addEventListener('load', onImgLoad, { capture: true })
+}
+
+const detachGalleryObservers = () => {
+  resizeObserver?.disconnect()
+  resizeObserver = null
+  gallery.value?.removeEventListener('load', onImgLoad, { capture: true })
+}
+
 onMounted(() => {
   const active = document.querySelector('.cursor') as HTMLElement | null
   if (active) {
@@ -419,16 +435,20 @@ onMounted(() => {
   }
   updateColumns()
   seedFromDocs()
-  if (gallery.value) {
-    resizeObserver = new ResizeObserver(updateColumns)
-    resizeObserver.observe(gallery.value)
-    gallery.value.addEventListener('load', onImgLoad, { capture: true })
-  }
+  attachGalleryObservers()
+})
+onActivated(() => {
+  nextTick(() => {
+    updateColumns()
+    attachGalleryObservers()
+  })
+})
+onDeactivated(() => {
+  detachGalleryObservers()
 })
 onUnmounted(() => {
   keyboardFollowScroll.cancel()
-  resizeObserver?.disconnect()
-  gallery.value?.removeEventListener('load', onImgLoad, { capture: true })
+  detachGalleryObservers()
 })
 
 // Re-seed aspect ratios whenever docs update (e.g., ar patch from server)

frontend/src/views/ExplorerView.vue

@@ -2,24 +2,20 @@
   <div class="transition-wrapper">
     <Transition
       :name="transitionName"
-      @after-enter="store.transitionDirection = 'none'"
+      @after-enter="onAfterEnter"
     >
-      <div :key="folderPath" class="explorer-content">
-        <Gallery
-          v-if="store.prefs.gallery"
+      <KeepAlive>
+        <component
+          :is="store.prefs.gallery ? Gallery : FileExplorer"
+          :key="cacheKey"
           ref="fileExplorer"
+          class="explorer-content"
           :path="props.path"
           :documents="documents"
         />
-        <FileExplorer
-          v-else
-          ref="fileExplorer"
-          :path="props.path"
-          :documents="documents"
-        />
-        <EmptyFolder :documents="documents" :path="props.path" />
-      </div>
+      </KeepAlive>
     </Transition>
+    <EmptyFolder :documents="documents" :path="props.path" />
   </div>
   <div v-if="store.searchLoading" class="search-loading">Searching...</div>
 </template>
@@ -31,7 +27,7 @@ import { getDocuments } from '@/stores/documentStore'
 import { useMainStore } from '@/stores/main'
 import { collator } from '@/utils'
 import { sorted, sortedGrouped } from '@/utils/docsort'
-import { computed, ref, watch, watchEffect } from 'vue'
+import { computed, nextTick, ref, watch, watchEffect } from 'vue'
 
 const store = useMainStore()
 const fileExplorer = ref()
@@ -42,6 +38,7 @@ const props = defineProps<{
 
 // Folder path for component keys - only recreate component when folder changes, not search
 const folderPath = computed(() => props.path.join('/'))
+const cacheKey = computed(() => `${store.prefs.gallery ? 'gallery' : 'list'}:${folderPath.value}`)
 
 const transitionName = computed(() => {
   if (store.transitionDirection === 'forward') return 'slide-forward'
@@ -49,6 +46,22 @@ const transitionName = computed(() => {
   return ''
 })
 
+const folderScrollTop = new Map<string, number>()
+const scrollKey = (path: string) => path || '/'
+const getMainScroller = () => document.querySelector('main') as HTMLElement | null
+
+const restoreScroll = (path: string) => {
+  const scroller = getMainScroller()
+  if (!scroller) return
+  const top = folderScrollTop.get(scrollKey(path)) ?? 0
+  scroller.scrollTop = top
+}
+
+const onAfterEnter = () => {
+  store.transitionDirection = 'none'
+  restoreScroll(folderPath.value)
+}
+
 // Handle route-based search changes (back/forward navigation, direct URL)
 // Skip if store.query already matches (means we triggered this via typing)
 watch(
@@ -101,6 +114,19 @@ watchEffect(() => {
   store.fileExplorer = fileExplorer.value
 })
 
+watch(
+  folderPath,
+  async (path, oldPath) => {
+    const scroller = getMainScroller()
+    if (scroller && oldPath !== undefined) {
+      folderScrollTop.set(scrollKey(oldPath), scroller.scrollTop)
+    }
+    await nextTick()
+    requestAnimationFrame(() => restoreScroll(path))
+  },
+  { immediate: true }
+)
+
 // Only auto-switch gallery mode when entering a new folder or on initial file list load
 watch(
   [() => props.path.join('/'), () => store.documentCount],

frontend/src/views/TextEditorView.vue

@@ -18,8 +18,16 @@ import { EditorView, keymap } from '@codemirror/view'
 import { basicSetup } from 'codemirror'
 import { apiFetch } from '@/repositories/Client'
 import { useMainStore } from '@/stores/main'
-import { computed, nextTick, onMounted, onUnmounted, ref } from 'vue'
-import { onBeforeRouteLeave, useRoute } from 'vue-router'
+import {
+  computed,
+  nextTick,
+  onActivated,
+  onDeactivated,
+  onMounted,
+  onUnmounted,
+  ref
+} from 'vue'
+import { useRoute } from 'vue-router'
 
 const route = useRoute()
 const store = useMainStore()
@@ -50,21 +58,32 @@ const languageCompartment = new Compartment()
 
 const dirty = computed(() => content.value !== original.value)
 
-onBeforeRouteLeave((_to, _from, next) => {
-  if (!dirty.value) {
-    next()
-    return
-  }
-  const discard = window.confirm('You have unsaved changes. Discard them?')
-  next(discard)
-})
-
 const beforeUnload = (event: BeforeUnloadEvent) => {
   if (!dirty.value) return
   event.preventDefault()
   event.returnValue = ''
 }
 
+let beforeUnloadActive = false
+
+const activateEditorBindings = () => {
+  store.editorSave = save
+  if (!beforeUnloadActive) {
+    window.addEventListener('beforeunload', beforeUnload)
+    beforeUnloadActive = true
+  }
+}
+
+const deactivateEditorBindings = () => {
+  if (store.editorSave === save) {
+    store.editorSave = null
+  }
+  if (beforeUnloadActive) {
+    window.removeEventListener('beforeunload', beforeUnload)
+    beforeUnloadActive = false
+  }
+}
+
 const detectLanguage = async () => {
   const language = LanguageDescription.matchFilename(languages, filename.value)
   if (!language) return []
@@ -129,8 +148,7 @@ const save = async () => {
 }
 
 onMounted(async () => {
-  store.editorSave = save
-  window.addEventListener('beforeunload', beforeUnload)
+  activateEditorBindings()
   loading.value = true
   error.value = ''
   try {
@@ -158,13 +176,18 @@ onMounted(async () => {
   }
 })
 
+onActivated(() => {
+  activateEditorBindings()
+})
+
+onDeactivated(() => {
+  deactivateEditorBindings()
+})
+
 onUnmounted(() => {
-  if (store.editorSave === save) {
-    store.editorSave = null
-  }
+  deactivateEditorBindings()
   editorView?.destroy()
   editorView = null
-  window.removeEventListener('beforeunload', beforeUnload)
 })
 </script>