lazy-load emoji-mart picker on web

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/components/EmojiPicker/index.web.tsx

@@ -1,5 +1,13 @@
-import {createContext, useContext, useEffect, useMemo, useRef} from 'react'
+import {
-import EmojiPicker from '@emoji-mart/react'
+  createContext,
+  lazy,
+  Suspense,
+  useContext,
+  useEffect,
+  useMemo,
+  useRef,
+} from 'react'
+import {View} from 'react-native'
 import {DropdownMenu} from 'radix-ui'
 
 import {useA11y} from '#/state/a11y'
@@ -16,6 +24,24 @@ import {
 
 export * from './types'
 
+/**
+ * The emoji-mart picker is code-split into its own chunk (`emoji-mart`) so its
+ * weight stays out of the main bundle and is only fetched when the picker
+ * actually mounts (i.e. when the dropdown opens). {@link useWebPreloadEmoji}
+ * warms the same chunk ahead of time.
+ */
+const EmojiPickerLazy = lazy(
+  () => import(/* webpackChunkName: "emoji-mart" */ '@emoji-mart/react'),
+)
+
+/**
+ * Fixed-size placeholder shown while the emoji-mart chunk loads, sized to match
+ * emoji-mart's default picker so the dropdown doesn't visually jump when the
+ * real picker mounts.
+ */
+const PICKER_WIDTH = 352
+const PICKER_HEIGHT = 435
+
 const EmojiPickerContext = createContext<{
   onEmojiSelect: (emoji: Emoji) => void
   nextFocusRef: RootProps['nextFocusRef']
@@ -124,7 +150,11 @@ export function Picker({keepOpenWhenShiftHeld = true}: PickerProps) {
         <div
           onWheel={evt => evt.stopPropagation()}
           style={flatten([!reduceMotionEnabled && a.zoom_fade_in])}>
-          <EmojiPicker
+          <Suspense
+            fallback={
+              <View style={{width: PICKER_WIDTH, height: PICKER_HEIGHT}} />
+            }>
+            <EmojiPickerLazy
               autoFocus
               onEmojiSelect={(emoji: Emoji) => {
                 onEmojiSelect(emoji)
@@ -134,6 +164,7 @@ export function Picker({keepOpenWhenShiftHeld = true}: PickerProps) {
                 }
               }}
             />
+          </Suspense>
         </div>
       </DropdownMenu.Content>
     </DropdownMenu.Portal>

src/components/EmojiPicker/preload.web.ts

@@ -1,5 +1,4 @@
 import {useCallback} from 'react'
-import {init} from 'emoji-mart'
 
 /**
  * Only load the emoji picker data once per page load.
@@ -21,7 +20,10 @@ export function useWebPreloadEmoji({immediate}: {immediate?: boolean} = {}) {
     if (loadRequested) return
     loadRequested = true
     try {
-      const data = (await import('@emoji-mart/data')).default
+      const [{init}, {default: data}] = await Promise.all([
+        import(/* webpackChunkName: "emoji-mart" */ 'emoji-mart'),
+        import(/* webpackChunkName: "emoji-mart-data" */ '@emoji-mart/data'),
+      ])
       init({data})
     } catch (e) {}
   }, [])