perf: skip RecentPostsWidget fetch when its rail is hidden on mobile

src/components/LibraryLayout.tsx

@@ -4,6 +4,7 @@ import { GithubIcon } from '~/components/icons/GithubIcon'
 import { DiscordIcon } from '~/components/icons/DiscordIcon'
 import { Link, useMatches, useParams } from '@tanstack/react-router'
 import { useLocalStorage } from '~/utils/useLocalStorage'
+import { useMediaQuery } from '~/utils/useMediaQuery'
 import { useClickOutside } from '~/hooks/useClickOutside'
 import { last } from '~/utils/utils'
 import type { ConfigSchema, MenuItem } from '~/utils/config'
@@ -424,26 +425,6 @@ function clampProgress(value: number) {
   return Math.min(Math.max(value, 0), 1)
 }
 
-function useMediaQuery(query: string) {
-  const [matches, setMatches] = React.useState(false)
-
-  React.useEffect(() => {
-    const mediaQueryList = window.matchMedia(query)
-    const updateMatches = () => {
-      setMatches(mediaQueryList.matches)
-    }
-
-    updateMatches()
-    mediaQueryList.addEventListener('change', updateMatches)
-
-    return () => {
-      mediaQueryList.removeEventListener('change', updateMatches)
-    }
-  }, [query])
-
-  return matches
-}
-
 function areDocsPartnerSlotsEqual(
   left: DocsPartnerScrollSlot | undefined,
   right: DocsPartnerScrollSlot | undefined,
@@ -903,6 +884,7 @@ export function LibraryLayout({
     surface: 'docs_rail',
   })
   const shouldShowDocsPartnerSlot = useMediaQuery('(max-width: 767.98px)')
+  const isDesktopViewport = useMediaQuery('(min-width: 768px)')
 
   const groupInitialOpenState = React.useMemo(() => {
     return visibleMenuConfig.reduce<Record<string, boolean>>(
@@ -1431,7 +1413,7 @@ export function LibraryLayout({
                   partners={activePartners}
                 />
                 <div className="hidden md:block border border-gray-500/20 rounded-l-lg overflow-hidden w-full">
-                  <RecentPostsWidget />
+                  <RecentPostsWidget enabled={isDesktopViewport} />
                 </div>
               </RightRail>
             )}

src/components/RecentPostsWidget.tsx

@@ -5,6 +5,8 @@ import { formatPublishedDate } from '~/utils/blog'
 
 type RecentPostsWidgetProps = {
   posts?: ReadonlyArray<RecentPost>
+  /** Set to false to skip the client fetch when the widget is rendered but not visible (e.g. hidden below a CSS breakpoint). Ignored when `posts` is provided. */
+  enabled?: boolean
 }
 
 function RecentPostsList({ posts }: { posts: ReadonlyArray<RecentPost> }) {
@@ -63,11 +65,14 @@ function RecentPostsSkeleton() {
   )
 }
 
-export function RecentPostsWidget({ posts }: RecentPostsWidgetProps) {
+export function RecentPostsWidget({
+  posts,
+  enabled = true,
+}: RecentPostsWidgetProps) {
   const recentPostsQuery = useQuery({
     queryKey: ['recentPosts'],
     queryFn: () => fetchRecentPosts(),
-    enabled: posts === undefined,
+    enabled: posts === undefined && enabled,
     staleTime: 1000 * 60 * 5,
   })
 

src/routes/blog.$.tsx

@@ -9,6 +9,7 @@ import { LibrariesWidget } from '~/components/LibrariesWidget'
 import { partners } from '~/utils/partners'
 import { PartnersRail, RightRail } from '~/components/RightRail'
 import { RecentPostsWidget } from '~/components/RecentPostsWidget'
+import { useMediaQuery } from '~/utils/useMediaQuery'
 
 import { Toc } from '~/components/Toc'
 import { Breadcrumbs } from '~/components/Breadcrumbs'
@@ -76,6 +77,7 @@ function BlogPost() {
   const headings = markdown.headings
 
   const isTocVisible = headings.length > 1
+  const isDesktopViewport = useMediaQuery('(min-width: 768px)')
 
   const markdownContainerRef = React.useRef<HTMLDivElement>(null)
   const [activeHeadings, setActiveHeadings] = React.useState<Array<string>>([])
@@ -203,7 +205,7 @@ function BlogPost() {
               partners={activePartners}
             />
             <div className="hidden md:block border border-gray-500/20 rounded-l-lg overflow-hidden w-full">
-              <RecentPostsWidget />
+              <RecentPostsWidget enabled={isDesktopViewport} />
             </div>
             <Card>
               <LibrariesWidget />

src/utils/useMediaQuery.ts

@@ -0,0 +1,21 @@
+import * as React from 'react'
+
+export function useMediaQuery(query: string) {
+  const [matches, setMatches] = React.useState(false)
+
+  React.useEffect(() => {
+    const mediaQueryList = window.matchMedia(query)
+    const updateMatches = () => {
+      setMatches(mediaQueryList.matches)
+    }
+
+    updateMatches()
+    mediaQueryList.addEventListener('change', updateMatches)
+
+    return () => {
+      mediaQueryList.removeEventListener('change', updateMatches)
+    }
+  }, [query])
+
+  return matches
+}