fix: dynamic tab sync

example/src/ConditionalTabs.tsx

@@ -1,6 +1,5 @@
 import React, { useState } from 'react'
-import { View, Text, StyleSheet } from 'react-native'
-import { TouchableOpacity } from 'react-native-gesture-handler'
+import { View, Text, StyleSheet, TouchableOpacity } from 'react-native'
 
 import ExampleComponent from './Shared/ExampleComponent'
 import { ExampleComponentType } from './types'

example/src/DynamicTabs.tsx

@@ -1,7 +1,6 @@
 import React from 'react'
-import { Text, View, StyleSheet } from 'react-native'
+import { Text, View, StyleSheet, TouchableOpacity } from 'react-native'
 import * as Tabs from 'react-native-collapsible-tab-view'
-import { TouchableOpacity } from 'react-native-gesture-handler'
 
 import { AlbumsContent } from './Shared/Albums'
 import { ArticleContent } from './Shared/Article'
@@ -75,7 +74,9 @@ const DynamicTabs: ExampleComponentType = () => {
   }
 
   const TabBarComponent = React.useCallback(
-    (props) => <Tabs.MaterialTabBar {...props} scrollEnabled />,
+    (props: Tabs.MaterialTabBarProps<string>) => (
+      <Tabs.MaterialTabBar {...props} scrollEnabled />
+    ),
     []
   )
 

src/Container.tsx

@@ -120,7 +120,7 @@ export const Container = React.memo(
       const accDiffClamp: ContextType['accDiffClamp'] = useSharedValue(0)
       const scrollYCurrent: ContextType['scrollYCurrent'] = useSharedValue(0)
       const scrollY: ContextType['scrollY'] = useSharedValue(
-        tabNamesArray.map(() => 0)
+        Object.fromEntries(tabNamesArray.map((n) => [n, 0]))
       )
 
       const contentHeights: ContextType['contentHeights'] = useSharedValue(
@@ -137,12 +137,6 @@ export const Container = React.memo(
           : 0
       )
 
-      const [data, setData] = React.useState(tabNamesArray)
-
-      React.useEffect(() => {
-        setData(tabNamesArray)
-      }, [tabNamesArray])
-
       const focusedTab: ContextType['focusedTab'] =
         useDerivedValue<TabName>(() => {
           return tabNames.value[index.value]
@@ -226,15 +220,22 @@ export const Container = React.memo(
         (i) => {
           if (i !== index.value) {
             offset.value =
-              scrollY.value[index.value] - scrollY.value[i] + offset.value
+              scrollY.value[tabNames.value[index.value]] -
+              scrollY.value[tabNames.value[i]] +
+              offset.value
             runOnJS(propagateTabChange)({
               prevIndex: index.value,
               index: i,
               prevTabName: tabNames.value[index.value],
               tabName: tabNames.value[i],
             })
             index.value = i
-            scrollYCurrent.value = scrollY.value[index.value] || 0
+            if (
+              typeof scrollY.value[tabNames.value[index.value]] === 'number'
+            ) {
+              scrollYCurrent.value =
+                scrollY.value[tabNames.value[index.value]] || 0
+            }
           }
         },
         []
@@ -433,13 +434,15 @@ export const Container = React.memo(
               {...pagerProps}
               style={[pagerProps?.style, StyleSheet.absoluteFill]}
             >
-              {data.map((tabName, i) => {
+              {tabNamesArray.map((tabName, i) => {
                 return (
                   <View key={i}>
                     <TabNameContext.Provider value={tabName}>
                       <Lazy
                         startMounted={lazy ? undefined : true}
                         cancelLazyFadeIn={!lazy ? true : !!cancelLazyFadeIn}
+                        // ensure that we remount the tab if its name changes but the index doesn't
+                        key={tabName}
                       >
                         {
                           React.Children.toArray(children)[

src/Lazy.tsx

@@ -68,14 +68,17 @@ export const Lazy: React.FC<{
     }
   }, [])
 
-  const startMountTimer = React.useCallback(() => {
-    // wait the scene to be at least mountDelay ms focused, before mounting
-    setTimeout(() => {
-      if (focusedTab.value === name) {
-        if (isSelfMounted.current) setCanMount(true)
-      }
-    }, mountDelayMs)
-  }, [focusedTab.value, mountDelayMs, name])
+  const startMountTimer = React.useCallback(
+    (focusedTab: string) => {
+      // wait the scene to be at least mountDelay ms focused, before mounting
+      setTimeout(() => {
+        if (focusedTab === name) {
+          if (isSelfMounted.current) setCanMount(true)
+        }
+      }, mountDelayMs)
+    },
+    [mountDelayMs, name]
+  )
 
   useAnimatedReaction(
     () => {
@@ -87,7 +90,7 @@ export const Lazy: React.FC<{
           opacity.value = 1
           runOnJS(setCanMount)(true)
         } else {
-          runOnJS(startMountTimer)()
+          runOnJS(startMountTimer)(focusedTab.value)
         }
       }
     },
@@ -116,7 +119,7 @@ export const Lazy: React.FC<{
     return {
       opacity: opacity.value,
     }
-  }, [])
+  }, [opacity])
 
   const onLayout = useCallback(() => {
     didTriggerLayout.value = true

src/hooks.tsx

@@ -249,7 +249,6 @@ export const useScrollHandlerY = (name: TabName) => {
     revealHeaderOnScroll,
     refMap,
     tabNames,
-    index,
     headerHeight,
     contentInset,
     containerHeight,
@@ -275,19 +274,13 @@ export const useScrollHandlerY = (name: TabName) => {
       enabled.value = toggle
 
       if (toggle) {
-        const tabIndex = tabNames.value.findIndex((n) => n === name)
-
         const ref = refMap[name]
-        scrollTo(
-          ref,
-          0,
-          scrollY.value[tabIndex],
-          false,
-          `[${name}] restore scroll position - enable`
-        )
+        const y = scrollY.value[name] ?? scrollYCurrent.value
+
+        scrollTo(ref, 0, y, false, `[${name}] restore scroll position - enable`)
       }
     },
-    [enabled, name, refMap, scrollTo, scrollY.value, tabNames.value]
+    [enabled, name, refMap, scrollTo, scrollY.value, scrollYCurrent.value]
   )
 
   /**
@@ -399,9 +392,9 @@ export const useScrollHandlerY = (name: TabName) => {
             scrollYCurrent.value = y
           }
 
-          scrollY.value[index.value] = scrollYCurrent.value
+          scrollY.value[name] = scrollYCurrent.value
           oldAccScrollY.value = accScrollY.value
-          accScrollY.value = scrollY.value[index.value] + offset.value
+          accScrollY.value = scrollY.value[name] + offset.value
 
           if (revealHeaderOnScroll) {
             const delta = accScrollY.value - oldAccScrollY.value
@@ -485,8 +478,8 @@ export const useScrollHandlerY = (name: TabName) => {
         focusedTab.value !== name
       ) {
         let nextPosition: number | null = null
-        const focusedScrollY = scrollY.value[Math.round(indexDecimal.value)]
-        const tabScrollY = scrollY.value[tabIndex]
+        const focusedScrollY = scrollY.value[focusedTab.value]
+        const tabScrollY = scrollY.value[name]
         const areEqual = focusedScrollY === tabScrollY
 
         if (!areEqual) {
@@ -514,7 +507,7 @@ export const useScrollHandlerY = (name: TabName) => {
 
         if (nextPosition !== null) {
           // console.log(`sync ${name} ${nextPosition}`)
-          scrollY.value[tabIndex] = nextPosition
+          scrollY.value[name] = nextPosition
           scrollTo(refMap[name], 0, nextPosition, false, `[${name}] sync pane`)
         }
       }
@@ -560,38 +553,17 @@ export function useAfterMountEffect(
   nextOnLayout: ViewProps['onLayout'],
   effect: React.EffectCallback
 ) {
-  const name = useTabNameContext()
-  const {
-    //tabsMounted,
-    refMap,
-    scrollY,
-    //scrollYCurrent,
-    tabNames,
-  } = useTabsContext()
-
   const didExecute = useRef(false)
   const didMount = useSharedValue(false)
 
-  const scrollTo = useScroller()
-  const ref = name ? refMap[name] : null
-
   useAnimatedReaction(
     () => {
       return didMount.value
     },
     (didMount, prevDidMount) => {
       if (didMount && !prevDidMount) {
         if (didExecute.current) return
-        if (ref) {
-          const tabIndex = tabNames.value.findIndex((n) => n === name)
-          scrollTo(
-            ref,
-            0,
-            scrollY.value[tabIndex],
-            false,
-            `[${name}] restore scroll position`
-          )
-        }
+
         effect()
         didExecute.current = true
       }

src/types.ts

@@ -168,7 +168,7 @@ export type ContextType<T extends TabName = TabName> = {
   /**
    * Array of the scroll y position of each tab.
    */
-  scrollY: SharedValue<number[]>
+  scrollY: SharedValue<Record<string, number>>
   containerHeight: SharedValue<number | undefined>
   /**
    * Object containing the ref of each scrollable component.

yarn.lock

@@ -6925,10 +6925,10 @@ human-signals@^5.0.0:
   resolved "https://registry.yarnpkg.com/human-signals/-/human-signals-5.0.0.tgz#42665a284f9ae0dade3ba41ebc37eb4b852f3a28"
   integrity sha512-AXcZb6vzzrFAUE61HnN4mpLqd/cSIwNQjtNWR0euPm6y0iqx3G4gOXaIDdtdDwZmhwe82LA6+zinmW4UBWVePQ==
 
-husky@7:
-  version "7.0.4"
-  resolved "https://registry.yarnpkg.com/husky/-/husky-7.0.4.tgz#242048245dc49c8fb1bf0cc7cfb98dd722531535"
-  integrity sha512-vbaCKN2QLtP/vD4yvs6iz6hBEo6wkSzs8HpRah1Z6aGmF2KW5PdYuAd7uX5a+OyBZHBhd+TFLqgjUgytQr4RvQ==
+husky@^9.0.11:
+  version "9.0.11"
+  resolved "https://registry.yarnpkg.com/husky/-/husky-9.0.11.tgz#fc91df4c756050de41b3e478b2158b87c1e79af9"
+  integrity sha512-AB6lFlbwwyIqMdHYhwPe+kjOC3Oc5P3nThEoW/AaO2BX3vJDjWPFxYLxokUZOo6RNX20He3AaT8sESs9NJcmEw==
 
 iconv-lite@^0.4.24:
   version "0.4.24"