Expo：未处理的 promise 拒绝：TypeError：未定义不是 object（评估“props.navigation”）]

Question

I have been working on React Native and I am getting this error any help will be appreciable!

My App.js Screen

 import React,{useEffect,useState} from "react"; import { NavigationContainer } from "@react-navigation/native"; import AppNavigator from "./navigation/AppNavigator"; export default function App() { return ( <NavigationContainer> <AppNavigator /> </NavigationContainer> ); }

My HomeScreen.js Screen

 import { StatusBar } from 'expo-status-bar'; import React from 'react'; import { StyleSheet, ActivityIndicator, Image,View,Text } from 'react-native'; import { Button, TextInput } from 'react-native-paper'; import AsyncStorage from '@react-native-async-storage/async-storage'; // <View style={styles.container}> const HomeScreen=(props)=> { const logout =(props)=>{ AsyncStorage.removeItem("token").then(()=>{ props.navigation.replace("login") }) } return ( <View style={styles.container}> <Text> Your Email is XYZ </Text> <Button style={styles.btnStyle} mode="contained" onPress={() => logout()} > LOG OUT </Button> </View> ); } const styles = StyleSheet.create({ container: { flex: 1, backgroundColor: '#fff', alignItems: 'center', fontSize:18, justifyContent: 'center', }, btnStyle: { marginLeft: 18, marginRight: 18, marginTop: 30, backgroundColor: "black", textShadowColor: "white", borderRadius: 35, }, }); export default HomeScreen;

My AppNavigator.js

 import React, { useEffect, useState } from "react"; import { createStackNavigator } from "@react-navigation/stack"; import SignUp from "../screens/SignupScreen"; import LoginScreen from "../screens/LoginScreen"; import LoadingScreen from "../screens/LoadingScreen"; import HomeScreen from "../screens/HomeScreen"; import AsyncStorage from '@react-native-async-storage/async-storage'; const Stack = createStackNavigator(); function AppNavigator() { const [isLoggedin, setLogged] = useState(null) useEffect(() => { const token = AsyncStorage.getItem('token') if (token) { setLogged(true) } else { setLogged(false) } }, []) return ( <Stack.Navigator headerMode="none" screenOptions={{ headerStyle: { elevation: 0 }, cardStyle: { backgroundColor: '#fff' } }} > <Stack.Screen name="loading" component={LoadingScreen}></Stack.Screen> <Stack.Screen name="home" component={HomeScreen}></Stack.Screen> <Stack.Screen name="login" component={LoginScreen}></Stack.Screen> <Stack.Screen name="signup" component={SignUp}></Stack.Screen> </Stack.Navigator> ); } export default AppNavigator;

The error I am getting is

[Unhandled promise rejection: TypeError: undefined is not an object (evaluating 'props.navigation')] at screens\HomeScreen.js:9:8 in logout at node_modules\react-native\node_modules\promise\setimmediate\core.js:37:13 in tryCallOne at node_modules\react-native\node_modules\promise\setimmediate\core.js:123:24 in setImmediate$argument_0 at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:130:14 in _callTimer at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:181:14 in _callImmediatesPass at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:441:30 in callImmediates at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:387:6 in __callImmediates at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:135:6 in __guard$argument_0 at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:364:10 in __guard at node_modules\react-native\Libraries\BatchedBridge\MessageQueue .js:134:4 in flushedQueue at [native code]:null in flushedQueue at [native code]:null in invokeCallbackAndReturnFlushedQueue

Answer 1

Your Stack.screens are not wrapped with NavigationContainer and navigation props is not passed down to your screens/components.

Please check https://reactnavigation.org/docs/hello-react-navigation

  return (
    <NavigationContainer>
      <Stack.Navigator
          headerMode="none"
          screenOptions={{
          headerStyle: { elevation: 0 },
          cardStyle: { backgroundColor: '#fff' }
     }}>
       <Stack.Screen name="signup" component={SignUp}></Stack.Screen>
       .....
     </Stack.Navigator>
   <NavigationContainer>
 );

Answer 2

In your HomeScreen.js change your Logout function to this -

  const logout = () => { // You were passing a props variable here that was undefined..
    AsyncStorage.removeItem('token').then(() => {
      props.navigation.replace('login');
    });
  };

Check out this Snack that I created... Just to show you the implementation

I would also suggest you to not restore token in your AppNavigator.js . Instead you should install expo-app-loading and restore your token inside your App.js

And also, its not a good practice to perform async operations inside a useEffect .. Check out the Snack link above for how you should implement it.. I've created a somewhat clone of it..Have a look