Unblock React Compiler for 18 components with value blocks inside try

React Compiler cannot lower a conditional expression - `&&`, `||`, `??`, `?.`,
a ternary - inside a try block. Three techniques, picked per site:

- split `if (a && b)` into nested ifs, where there is no `else` to break
- hoist the expression into a const above the try, where it does not depend on
  anything the try produces
- move it into a module-scope helper, where it does

Optional calls become `if (f) f()`, which keeps the arguments unevaluated when
the callback is absent, exactly as `f?.()` does.

Skipped components: 125 -> 107.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/components/Dialog/index.web.tsx

@@ -73,12 +73,16 @@ export function Outer({
       setIsOpen(false)
 
       try {
-        if (cb && typeof cb === 'function') {
+        // Nested rather than `&&`: React Compiler cannot lower a logical
-          // This timeout ensures that the callback runs at the same time as it would on native. I.e.
+        // expression in a test position inside a `try`.
-          // console.log('Step 1') -> close(() => console.log('Step 3')) -> console.log('Step 2')
+        if (cb) {
-          // This should always output 'Step 1', 'Step 2', 'Step 3', but without the timeout it would output
+          if (typeof cb === 'function') {
-          // 'Step 1', 'Step 3', 'Step 2'.
+            // This timeout ensures that the callback runs at the same time as it would on native. I.e.
-          setTimeout(cb)
+            // console.log('Step 1') -> close(() => console.log('Step 3')) -> console.log('Step 2')
+            // This should always output 'Step 1', 'Step 2', 'Step 3', but without the timeout it would output
+            // 'Step 1', 'Step 3', 'Step 2'.
+            setTimeout(cb)
+          }
         }
       } catch (e: any) {
         logger.error(`Dialog closeCallback failed`, {

src/components/FeedCard.tsx

@@ -295,6 +295,8 @@ function SaveButtonInner({
       e.preventDefault()
       e.stopPropagation()
 
+      const pinned = pin || false
+
       try {
         if (savedFeedConfig) {
           await removeFeed(savedFeedConfig)
@@ -303,7 +305,7 @@ function SaveButtonInner({
             {
               type,
               value: uri,
-              pinned: pin || false,
+              pinned,
             },
           ])
         }

src/components/PostControls/index.tsx

@@ -107,9 +107,10 @@ let PostControls = ({
       return
     }
 
+    const existingLike = post.viewer?.like
     try {
       setHasLikeIconBeenToggled(true)
-      if (!post.viewer?.like) {
+      if (!existingLike) {
         sendInteraction({
           item: post.uri,
           event: 'app.bsky.feed.defs#interactionLike',
@@ -137,8 +138,9 @@ let PostControls = ({
       return
     }
 
+    const existingRepost = post.viewer?.repost
     try {
-      if (!post.viewer?.repost) {
+      if (!existingRepost) {
         sendInteraction({
           item: post.uri,
           event: 'app.bsky.feed.defs#interactionRepost',

src/components/ProfileCard.tsx

@@ -491,16 +491,21 @@ export function FollowButtonInner({
   const onPressFollow = async (e: GestureResponderEvent) => {
     e.preventDefault()
     e.stopPropagation()
+    const displayNameOrHandle = profile.displayName || profile.handle
     try {
       await queueFollow()
       Toast.show(
         l`Following ${sanitizeDisplayName(
-          profile.displayName || profile.handle,
+          displayNameOrHandle,
           moderation.ui('displayName'),
         )}`,
       )
-      onPressProp?.(e)
+      if (onPressProp) {
-      onFollow?.()
+        onPressProp(e)
+      }
+      if (onFollow) {
+        onFollow()
+      }
     } catch (e) {
       const err = e as Error
       if (err?.name !== 'AbortError') {
@@ -514,15 +519,18 @@ export function FollowButtonInner({
   const onPressUnfollow = async (e: GestureResponderEvent) => {
     e.preventDefault()
     e.stopPropagation()
+    const displayNameOrHandle = profile.displayName || profile.handle
     try {
       await queueUnfollow()
       Toast.show(
         l`No longer following ${sanitizeDisplayName(
-          profile.displayName || profile.handle,
+          displayNameOrHandle,
           moderation.ui('displayName'),
         )}`,
       )
-      onPressProp?.(e)
+      if (onPressProp) {
+        onPressProp(e)
+      }
     } catch (e) {
       const err = e as Error
       if (err?.name !== 'AbortError') {

src/components/dialogs/lists/CreateOrEditListDialog.tsx

@@ -221,6 +221,14 @@ function DialogInner({
   const onPressSave = useCallback(async () => {
     setImageError('')
     setDisplayNameTooShort(false)
+    // Hoisted above the `try`: React Compiler cannot lower a conditional
+    // expression inside one.
+    const updatedMessage = isCurateList
+      ? _(msg({message: 'User list updated', context: 'toast'}))
+      : _(msg({message: 'Moderation list updated', context: 'toast'}))
+    const createdMessage = isCurateList
+      ? _(msg({message: 'User list created', context: 'toast'}))
+      : _(msg({message: 'Moderation list created', context: 'toast'}))
     try {
       if (displayName.length === 0) {
         setDisplayNameTooShort(true)
@@ -244,11 +252,7 @@ function DialogInner({
           descriptionFacets: richText.facets,
           avatar: newListAvatar,
         })
-        Toast.show(
+        Toast.show(updatedMessage)
-          isCurateList
-            ? _(msg({message: 'User list updated', context: 'toast'}))
-            : _(msg({message: 'Moderation list updated', context: 'toast'})),
-        )
         control.close(() => onSave?.(list.uri))
       } else {
         const {uri} = await createListMutation({
@@ -258,11 +262,7 @@ function DialogInner({
           descriptionFacets: richText.facets,
           avatar: newListAvatar,
         })
-        Toast.show(
+        Toast.show(createdMessage)
-          isCurateList
-            ? _(msg({message: 'User list created', context: 'toast'}))
-            : _(msg({message: 'Moderation list created', context: 'toast'})),
-        )
         control.close(() => onSave?.(uri))
       }
     } catch (e: any) {

src/screens/CustomFeed/components/CustomFeedHeader.tsx

@@ -450,10 +450,14 @@ function DialogInner({
   const feedRkey = useMemo(() => new AtUri(info.uri).rkey, [info.uri])
 
   const onToggleLiked = async () => {
+    // Hoisted out of the `try`: React Compiler cannot lower a logical
+    // expression in a test position there, and the `else` below rules out
+    // splitting this into nested ifs.
+    const shouldUnlike = isLiked && likeUri
     try {
       playHaptic()
 
-      if (isLiked && likeUri) {
+      if (shouldUnlike) {
         await unlikeFeed({uri: likeUri})
         setLikeUri('')
         ax.metric('feed:unlike', {feedUrl: info.uri})

src/screens/ModerationInteractionSettings/index.tsx

@@ -95,11 +95,13 @@ function Inner({preferences}: {preferences: UsePreferencesQueryResponse}) {
   const onSave = useCallback(async () => {
     setError('')
 
+    const embeddingRules = maybeEditedPostgate.embeddingRules ?? []
+
     try {
       await setPostInteractionSettings({
         threadgateAllowRules:
           threadgateAllowUISettingToAllowRecordValue(maybeEditedAllowUI),
-        postgateEmbeddingRules: maybeEditedPostgate.embeddingRules ?? [],
+        postgateEmbeddingRules: embeddingRules,
       })
       Toast.show(_(msg({message: 'Settings saved', context: 'toast'})))
     } catch (e: any) {

src/screens/Onboarding/StepFinished/index.tsx

@@ -78,11 +78,12 @@ export function StepFinished() {
         logger.error('Failed to fetch starter pack', {safeMessage: e})
         // don't tell the user, just get them through onboarding.
       }
+      const starterPackList = starterPack?.list
       try {
-        if (starterPack?.list) {
+        if (starterPackList) {
           listItems = await getAllListMembers(
             appviewClient,
-            starterPack.list.uri,
+            starterPackList.uri,
           )
         }
       } catch (e) {
@@ -93,19 +94,22 @@ export function StepFinished() {
       }
     }
 
+    // Hoisted above the `try`: React Compiler cannot lower these inside one, and
+    // `listItems` is already settled by the earlier try/catch.
+    const followDids = [
+      BSKY_APP_ACCOUNT_DID,
+      ...(listItems?.map(i => i.subject.did) ?? []),
+    ]
+    const starterPackRef = starterPack
+      ? {uri: starterPack.uri, cid: starterPack.cid}
+      : undefined
+
     try {
       const {interestsStepResults, profileStepResults} = state
       const {selectedInterests} = interestsStepResults
 
       await Promise.all([
-        bulkWriteFollows(
+        bulkWriteFollows(pdsClient, appviewClient, followDids, starterPackRef),
-          pdsClient,
-          appviewClient,
-          [BSKY_APP_ACCOUNT_DID, ...(listItems?.map(i => i.subject.did) ?? [])],
-          starterPack
-            ? {uri: starterPack.uri, cid: starterPack.cid}
-            : undefined,
-        ),
         (async () => {
           // Interests need to get saved first, then we can write the feeds to prefs
           await pdsClient.call(setInterestsPref, {tags: selectedInterests})

src/screens/Profile/Header/ProfileHeaderLabeler.tsx

@@ -259,6 +259,9 @@ export function HeaderLabelerButtons({
     requireAuth(async (): Promise<void> => {
       playHaptic()
       const subscribe = !isSubscribed
+      const subscribeMetric = subscribe
+        ? 'moderation:subscribedToLabeler'
+        : 'moderation:unsubscribedFromLabeler'
 
       try {
         await toggleSubscription({
@@ -266,12 +269,7 @@ export function HeaderLabelerButtons({
           subscribe,
         })
 
-        ax.metric(
+        ax.metric(subscribeMetric, {})
-          subscribe
-            ? 'moderation:subscribedToLabeler'
-            : 'moderation:unsubscribedFromLabeler',
-          {},
-        )
       } catch (e: any) {
         reset()
         if (e.message === 'MAX_LABELERS') {

src/screens/Profile/Header/ProfileHeaderStandard.tsx

@@ -238,14 +238,17 @@ export function HeaderStandardButtons({
 
   const onPressFollow = () => {
     playHaptic()
+    const displayNameOrHandle = profile.displayName || profile.handle
     requireAuth(async () => {
       try {
         await queueFollow()
-        onFollow?.()
+        if (onFollow) {
+          onFollow()
+        }
         Toast.show(
           _(
             msg`Following ${sanitizeDisplayName(
-              profile.displayName || profile.handle,
+              displayNameOrHandle,
               moderation.ui('displayName'),
             )}`,
           ),
@@ -264,14 +267,17 @@ export function HeaderStandardButtons({
 
   const onPressUnfollow = () => {
     playHaptic()
+    const displayNameOrHandle = profile.displayName || profile.handle
     requireAuth(async () => {
       try {
         await queueUnfollow()
-        onUnfollow?.()
+        if (onUnfollow) {
+          onUnfollow()
+        }
         Toast.show(
           _(
             msg`No longer following ${sanitizeDisplayName(
-              profile.displayName || profile.handle,
+              displayNameOrHandle,
               moderation.ui('displayName'),
             )}`,
           ),

src/screens/ProfileList/components/Header.tsx

@@ -64,6 +64,12 @@ export function Header({
   const onTogglePinned = async () => {
     playHaptic()
 
+    // Hoisted above the `try`: inside it, `pinned` is `!savedFeedConfig.pinned`,
+    // which is `!isPinned` on the branch that uses this.
+    const pinnedMessage = !isPinned
+      ? _(msg`Pinned to your feeds`)
+      : _(msg`Unpinned from your feeds`)
+
     try {
       if (savedFeedConfig) {
         const pinned = !savedFeedConfig.pinned
@@ -73,11 +79,7 @@ export function Header({
             pinned,
           },
         ])
-        Toast.show(
+        Toast.show(pinnedMessage)
-          pinned
-            ? _(msg`Pinned to your feeds`)
-            : _(msg`Unpinned from your feeds`),
-        )
       } else {
         await addSavedFeeds([
           {

src/screens/Signup/StepCaptcha/CaptchaWebView.web.tsx

@@ -5,6 +5,15 @@ import {type CaptchaWebViewProps} from './CaptchaWebView.shared'
 
 const REDIRECT_HOST = new URL(window.location.href).host
 
+/**
+ * Module scope because React Compiler cannot lower an optional chain inside a
+ * `try`, and this one has to stay in the `try` - reading `location` on a
+ * cross-origin frame throws.
+ */
+function getFrameHref(frame: HTMLIFrameElement | null): string | undefined {
+  return frame?.contentWindow?.location.href
+}
+
 export function CaptchaWebView({
   url,
   stateParam,
@@ -29,7 +38,7 @@ export function CaptchaWebView({
     ) as HTMLIFrameElement
 
     try {
-      const href = frame?.contentWindow?.location.href
+      const href = getFrameHref(frame)
       if (!href) return
       const urlp = new URL(href)
 
@@ -37,7 +46,12 @@ export function CaptchaWebView({
       if (urlp.host !== REDIRECT_HOST) return
 
       const code = urlp.searchParams.get('code')
-      if (urlp.searchParams.get('state') !== stateParam || !code) {
+      const stateMismatch = urlp.searchParams.get('state') !== stateParam
+      if (stateMismatch) {
+        onError({error: 'Invalid state or code'})
+        return
+      }
+      if (!code) {
         onError({error: 'Invalid state or code'})
         return
       }

src/state/queries/join-links.ts

@@ -261,7 +261,10 @@ export function useGetJoinLinkPreview() {
           staleTime: STALE.SECONDS.FIFTEEN,
         })
         const found = data.joinLinkPreviews[0]
-        return isKnownJoinLinkPreview(found) ? found : undefined
+        if (isKnownJoinLinkPreview(found)) {
+          return found
+        }
+        return undefined
       } catch (error) {
         logger.error('Failed to fetch join link preview', {safeMessage: error})
         return undefined

src/state/queries/service-config.ts

@@ -13,6 +13,22 @@ type ServiceConfig = {
   }[]
 }
 
+/**
+ * Module scope because React Compiler cannot lower a `??` inside a `try`, and
+ * `data` only exists once the request in that `try` resolves.
+ */
+function toServiceConfig(data: {
+  checkEmailConfirmed?: boolean
+  liveNow?: ServiceConfig['liveNow']
+}): ServiceConfig {
+  return {
+    checkEmailConfirmed: Boolean(data.checkEmailConfirmed),
+    // @ts-expect-error not included in the lexicon atm
+    topicsEnabled: Boolean(data.topicsEnabled),
+    liveNow: data.liveNow ?? [],
+  }
+}
+
 export function useServiceConfigQuery() {
   const client = useAppviewClient()
   return useQuery<ServiceConfig>({
@@ -22,12 +38,7 @@ export function useServiceConfigQuery() {
     queryFn: async () => {
       try {
         const data = await client.call(app.bsky.unspecced.getConfig)
-        return {
+        return toServiceConfig(data)
-          checkEmailConfirmed: Boolean(data.checkEmailConfirmed),
-          // @ts-expect-error not included in the lexicon atm
-          topicsEnabled: Boolean(data.topicsEnabled),
-          liveNow: data.liveNow ?? [],
-        }
       } catch (e) {
         return {
           checkEmailConfirmed: false,

src/view/com/composer/drafts/DraftItem.tsx

@@ -287,9 +287,10 @@ function DraftMediaPreview({post}: {post: DraftPostDisplay}) {
       if (post.images && post.images.length > 0) {
         const loaded: LoadedImage[] = []
         for (const image of post.images) {
+          const alt = image.altText || ''
           try {
             const url = await storage.loadMediaFromLocal(image.localPath)
-            loaded.push({url, alt: image.altText || ''})
+            loaded.push({url, alt})
           } catch (e) {
             // Image doesn't exist locally, skip it
           }

src/view/com/composer/photos/OpenCameraBtn.tsx

@@ -1,4 +1,3 @@
-import {useCallback} from 'react'
 import * as MediaLibrary from 'expo-media-library/legacy'
 import {msg} from '@lingui/core/macro'
 import {useLingui} from '@lingui/react'
@@ -20,13 +19,21 @@ export function OpenCameraBtn({disabled, onAdd}: OpenCameraBtnProps) {
     MediaLibrary.usePermissions({granularPermissions: ['photo']})
   const t = useTheme()
 
-  const onPressTakePicture = useCallback(async () => {
+  const mediaGranted = mediaPermissionRes?.granted
+  const mediaCanAskAgain = mediaPermissionRes?.canAskAgain
+
+  // No useCallback: with the diagnostics above resolved this component compiles,
+  // so React Compiler memoizes it, and the hand-written deps were what it could
+  // not preserve.
+  const onPressTakePicture = async () => {
     try {
       if (!(await requestCameraAccessIfNeeded())) {
         return
       }
-      if (!mediaPermissionRes?.granted && mediaPermissionRes?.canAskAgain) {
+      if (!mediaGranted) {
-        await requestMediaPermission()
+        if (mediaCanAskAgain) {
+          await requestMediaPermission()
+        }
       }
 
       const img = await openCamera({
@@ -49,12 +56,7 @@ export function OpenCameraBtn({disabled, onAdd}: OpenCameraBtnProps) {
       // ignore
       logger.warn('Error using camera', {error: err})
     }
-  }, [
+  }
-    onAdd,
-    requestCameraAccessIfNeeded,
-    mediaPermissionRes,
-    requestMediaPermission,
-  ])
 
   const shouldShowCameraButton = IS_NATIVE || IS_WEB_MOBILE
   if (!shouldShowCameraButton) {

src/view/com/feeds/ComposerPrompt.tsx

@@ -56,8 +56,10 @@ export function ComposerPrompt() {
         requestVideoAccessIfNeeded(),
       ])
 
-      if (!photoAccess && !videoAccess) {
+      if (!photoAccess) {
-        return
+        if (!videoAccess) {
+          return
+        }
       }
 
       if (Keyboard.isVisible()) {
@@ -108,8 +110,10 @@ export function ComposerPrompt() {
         return
       }
 
-      if (IS_NATIVE && Keyboard.isVisible()) {
+      if (IS_NATIVE) {
-        Keyboard.dismiss()
+        if (Keyboard.isVisible()) {
+          Keyboard.dismiss()
+        }
       }
 
       const image = await openCamera({
@@ -127,8 +131,14 @@ export function ComposerPrompt() {
         },
       ]
 
+      // Statement form rather than a ternary: React Compiler cannot lower a
+      // conditional expression inside a `try`, and `imageUris` is built here.
+      let nativeImageUris
+      if (IS_NATIVE) {
+        nativeImageUris = imageUris
+      }
       openComposer({
-        imageUris: IS_NATIVE ? imageUris : undefined,
+        imageUris: nativeImageUris,
         logContext: 'Fab',
       })
     } catch (err: any) {

src/view/com/util/UserBanner.tsx

@@ -79,15 +79,20 @@ export function UserBanner({
 
     try {
       if (IS_NATIVE) {
-        onSelectNewBanner?.(
+        // Nested rather than `?.()`: React Compiler cannot lower an optional
-          await compressIfNeeded(
+        // call inside a `try`. Like `?.()`, this leaves the arguments
-            await openCropper({
+        // unevaluated when the callback is absent.
-              imageUri: items[0].path,
+        if (onSelectNewBanner) {
-              aspectRatio: 3 / 1,
+          onSelectNewBanner(
-            }),
+            await compressIfNeeded(
-            IMAGE_SIZE_CONFIG_2K_1MB,
+              await openCropper({
-          ),
+                imageUri: items[0].path,
-        )
+                aspectRatio: 3 / 1,
+              }),
+              IMAGE_SIZE_CONFIG_2K_1MB,
+            ),
+          )
+        }
       } else {
         setRawImage(await createComposerImage(items[0]))
         editImageDialogControl.open()