frontend/src/components/PrefetchLink.tsx

@@ -1,15 +1,16 @@
 import { useQueryClient } from '@tanstack/react-query'
 import { useMemo } from 'react'
-import { useNavigate } from 'react-router-dom'
+import { createPath, useNavigate } from 'react-router-dom'
 
 import { useOverlayStore } from '@/components/RouteBlockerOverlay'
 import { prefetchForURL } from '@/lib/prefetchers'
 import { cn } from '@/lib/utils'
 
 import type { AnchorHTMLAttributes, FC, MouseEvent, TouchEvent } from 'react'
+import type { To } from 'react-router-dom'
 
 type Props = AnchorHTMLAttributes<HTMLAnchorElement> & {
-    to:             string
+    to:             To
     replace?:       boolean
     className?:     string
     cancelOnError?: boolean }
@@ -25,7 +26,10 @@ export default (({ to,
 		   ...rest }: Props) => {
   const navigate = useNavigate ()
   const qc = useQueryClient ()
-  const url = useMemo (() => (new URL (to, location.origin)).toString (), [to])
+  const url = useMemo (() => {
+    const path = (typeof to === 'string') ? to : createPath (to)
+    return (new URL (path, location.origin)).toString ()
+  }, [to])
   const setOverlay = useOverlayStore (s => s.setActive)
 
   const doPrefetch = async () => {
@@ -74,7 +78,7 @@ export default (({ to,
   }
 
   return (
-      <a href={to}
+      <a href={typeof to === 'string' ? to : createPath (to)}
 	 onMouseEnter={handleMouseEnter}
 	 onTouchStart={handleTouchStart}
 	 onClick={handleClick}

frontend/src/components/TagLink.tsx

@@ -1,5 +1,6 @@
 import { Link } from 'react-router-dom'
 
+import PrefetchLink from '@/components/PrefetchLink'
 import { LIGHT_COLOUR_SHADE, DARK_COLOUR_SHADE, TAG_COLOUR } from '@/consts'
 import { cn } from '@/lib/utils'
 
@@ -9,7 +10,8 @@ import type { Tag } from '@/types'
 
 type CommonProps = { tag:         Tag
 		     withWiki?:   boolean
-		     withCount?:  boolean }
+		     withCount?:  boolean
+		     prefetch?:   boolean }
 
 type PropsWithLink =
     CommonProps & { linkFlg?: true } & Partial<ComponentProps<typeof Link>>
@@ -24,6 +26,7 @@ export default (({ tag,
 		   linkFlg   = true,
 		   withWiki  = true,
 		   withCount = true,
+		   prefetch  = false,
 		   ...props }: Props) => {
   const spanClass = cn (
       `text-${ TAG_COLOUR[tag.category] }-${ LIGHT_COLOUR_SHADE }`,
@@ -44,11 +47,19 @@ export default (({ tag,
 	    </span>)}
 	{linkFlg
 	 ? (
-	    <Link to={`/posts?${ (new URLSearchParams ({ tags: tag.name })).toString () }`}
+	    prefetch
+	    ? <PrefetchLink
+		  to={`/posts?${ (new URLSearchParams ({ tags: tag.name })).toString () }`}
 		  className={linkClass}
 		  {...props}>
-	      {tag.name}
+		{tag.name}
-	    </Link>)
+	      </PrefetchLink>
+	    : <Link
+		  to={`/posts?${ (new URLSearchParams ({ tags: tag.name })).toString () }`}
+		  className={linkClass}
+		  {...props}>
+		{tag.name}
+	      </Link>)
 	 : (
 	    <span className={spanClass}
 		  {...props}>

frontend/src/components/TagSidebar.tsx

@@ -10,16 +10,17 @@ import { API_BASE_URL } from '@/config'
 import { CATEGORIES } from '@/consts'
 import { cn } from '@/lib/utils'
 
-import type { FC } from 'react'
+import type { FC, MouseEvent } from 'react'
 
 import type { Post, Tag } from '@/types'
 
 type TagByCategory = Record<string, Tag[]>
 
-type Props = { posts: Post[] }
+type Props = { posts:     Post[]
+	       onClick?:  (event: MouseEvent<HTMLElement>) => void }
 
 
-export default (({ posts }: Props) => {
+export default (({ posts, onClick }: Props) => {
   const navigate = useNavigate ()
 
   const [tagsVsbl, setTagsVsbl] = useState (false)
@@ -64,11 +65,11 @@ export default (({ posts }: Props) => {
 	<div className={cn (!(tagsVsbl) && 'hidden', 'md:block mt-4')}>
 	  <SectionTitle>タグ</SectionTitle>
 	  <ul>
-	    {CATEGORIES.flatMap (cat => cat in tags ? (
+	    {CATEGORIES.flatMap (cat => cat in tags ?
 		tags[cat].map (tag => (
 		    <li key={tag.id} className="mb-1">
-		      <TagLink tag={tag}/>
+		      <TagLink tag={tag} prefetch onClick={onClick}/>
-		    </li>))) : [])}
+		    </li>)) : [])}
 	  </ul>
 	  <SectionTitle>関聯</SectionTitle>
 	  {posts.length > 0 && (

frontend/src/pages/posts/PostListPage.tsx

@@ -10,6 +10,7 @@ import WikiBody from '@/components/WikiBody'
 import TabGroup, { Tab } from '@/components/common/TabGroup'
 import MainArea from '@/components/layout/MainArea'
 import { API_BASE_URL, SITE_TITLE } from '@/config'
+import { fetchPosts } from '@/lib/posts'
 
 import type { Post, WikiPage } from '@/types'
 
@@ -28,13 +29,11 @@ export default () => {
   const loadMore = async (withCursor: boolean) => {
     setLoading (true)
 
-    const res = await axios.get (`${ API_BASE_URL }/posts`, {
+    const data = await fetchPosts ({
-	params: { tags:   tags.join (' '),
+	tags:   tags.join (' '),
-		  match:  anyFlg ? 'any' : 'all',
+	match:  anyFlg ? 'any' : 'all',
-		  limit:  '20',
+	limit:  20,
-		  ...(withCursor && { cursor }) } })
+	...(withCursor && { cursor }) })
-    const data = toCamel (res.data as any, { deep: true }) as { posts:      Post[]
-								nextCursor: string }
     setPosts (posts => (
 	[...((new Map ([...(withCursor ? posts : []), ...data.posts]
 		       .map (post => [post.id, post])))
@@ -111,7 +110,13 @@ export default () => {
 	  </title>
 	</Helmet>
 
-	<TagSidebar posts={posts.slice (0, 20)}/>
+	<TagSidebar posts={posts.slice (0, 20)} onClick={() => {
+	    const statesToSave = {
+		posts, cursor,
+		scroll: containerRef.current?.scrollTop ?? 0 }
+	    sessionStorage.setItem (`posts:${ tagsQuery }`,
+				    JSON.stringify (statesToSave))
+	}}/>
 
 	<MainArea>
 	  <TabGroup>