fix: make @react-navigation/native an optional peer dependency (#770)

The SDK imported `useIsFocused` directly from `@react-navigation/native`
in the IterableInbox component, causing build failures for apps that do
not use React Navigation. This change introduces a wrapper hook that
tries to load `useIsFocused` from `@react-navigation/native` at module
load time and falls back to always returning `true` when the package is
not installed. The peer dependency is also marked as optional in
peerDependenciesMeta.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: sumchattering

package.json

@@ -118,6 +118,9 @@
     "react-native-webview": "*"
   },
   "peerDependenciesMeta": {
+    "@react-navigation/native": {
+      "optional": true
+    },
     "expo": {
       "optional": true
     }

src/core/hooks/index.ts

@@ -1,2 +1,3 @@
 export * from './useAppStateListener';
 export * from './useDeviceOrientation';
+export * from './useIsFocused';

src/core/hooks/useIsFocused.ts

@@ -0,0 +1,45 @@
+/**
+ * The type of the `useIsFocused` hook from `@react-navigation/native`.
+ */
+type UseIsFocusedHook = () => boolean;
+
+let _useIsFocused: UseIsFocusedHook | undefined;
+
+/**
+ * Attempts to load `useIsFocused` from `@react-navigation/native`.
+ *
+ * This is done once at module load time. If the package is not installed,
+ * the import will fail and `_useIsFocused` will remain `undefined`.
+ */
+try {
+  // eslint-disable-next-line @typescript-eslint/no-var-requires, @typescript-eslint/no-require-imports
+  _useIsFocused = require('@react-navigation/native').useIsFocused;
+} catch {
+  // @react-navigation/native is not installed; this is fine.
+}
+
+/**
+ * A fallback hook that always returns `true`.
+ *
+ * Used when `@react-navigation/native` is not installed. Since there is no
+ * navigation container managing focus, the component is always considered
+ * focused.
+ *
+ * @returns `true`
+ */
+function useAlwaysFocused(): boolean {
+  return true;
+}
+
+/**
+ * A hook that returns whether the screen is currently focused.
+ *
+ * If `@react-navigation/native` is installed, this delegates to its
+ * `useIsFocused` hook. Otherwise, it falls back to always returning `true`,
+ * which is appropriate when no navigation container is in use (the component
+ * is always "focused" if there is no navigation stack managing focus).
+ *
+ * @returns `true` if the screen is focused (or if React Navigation is not
+ * installed), `false` otherwise.
+ */
+export const useIsFocused: UseIsFocusedHook = _useIsFocused ?? useAlwaysFocused;

src/inbox/components/IterableInbox.tsx

@@ -1,4 +1,3 @@
-import { useIsFocused } from '@react-navigation/native';
 import { useEffect, useState } from 'react';
 import {
   Animated,
@@ -11,7 +10,11 @@ import {
 import { SafeAreaView } from 'react-native-safe-area-context';
 
 import RNIterableAPI from '../../api';
-import { useAppStateListener, useDeviceOrientation } from '../../core';
+import {
+  useAppStateListener,
+  useDeviceOrientation,
+  useIsFocused,
+} from '../../core';
 // expo throws an error if this is not imported directly due to circular
 // dependencies
 // See: https://github.com/expo/expo/issues/35100