Build a great login experience with React Native, Axios and JSONWebToken

We Have to Done Following steps.

1. We want a backend API
2. We want react-native project Version: 0.60 or up
3. We will use JSON web token
4. Axios
5. React-native navigation Version: 6.x
6. Stack navigation
7. AsyncStroge

Maybe that’s enough for this

Let’s start our project.

Make our project by using following command

npx react-native init Athentication_belog

Here is your new project looks like

Now go to your terminal and write following command in your terminal.

cd Athentication_belog

After this now install react native navigation by using

yarn add @react-navigation/native

Or if you are using npm then use following command

npm install @react-navigation/native

following is the official link of react-native navigation

https://reactnavigation.org/docs/getting-started

we also need to install following dependencies

yarn add react-native-screens react-native-safe-area-context

Or if you are using npm then use following command

npm install react-native-screens react-native-safe-area-context

for using navigation, you have to edit

your MainActicity.java Which is located android/app/src/main/java/<your package name>/MainActivity.java.

Add the following code to the body of MainActivity class:

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(null);
}

and make sure to add the following import statement at the top of this file below your package statement:

import android.os.Bundle;

now install react-native stack dependency

yarn add @react-navigation/native-stack 

now run your application using

npx react-native run-android

and in another terminal

npx react-native start

your android screen looks like

Now clean up your App.js and add the following code.

import React from 'react';
import {View} from 'react-native';
import {NavigationContainer} from '@react-navigation/native';
const App = () => {
  return (
    <View>
    <NavigationContainer>

     {/* Rest of your app code */}

    </NavigationContainer>
    </View>
  );
};

export default App;

create a folder root src/ Navigation/Stack.js and paste following code

import React from 'react';
import {createNativeStackNavigator} from '@react-navigation/native-stack';
const Stack = () => {
  const Stack = createNativeStackNavigator();
  return (
    <Stack.Navigator>
 
   <Stack.Screen name="Home" component={HomeScreen} />
    
    </Stack.Navigator>
  );
};

export default Stack;

and update your App.js file with following code

import React from 'react'; 
import {NavigationContainer} from '@react-navigation/native';
import StackScreen from './src/Navigation/Stack';

const App = () => {
  return (
    <NavigationContainer>
      <StackScreen />
    </NavigationContainer>
  );
};

export default App;

Now Create Screens Screen/Home/Home.js and put the code

import React from 'react';
import {View, Text, Button} from 'react-native';

const HomeScreen = ({navigation}) => {
  const logOutScreen = () => {
    
  };

  return (
    <View
      style={{
        display: 'flex',
        justifyContent: 'center',
        alignItems: 'center',
        height: '100%',
        backgroundColor: '#FFFFFF',
        width: '100%',
      }}>
      <Text style={{color: '#333'}}>HomeScreen</Text>
      <View style={{marginTop: 10}}>
        <Button title="logOut" onPress={logOutScreen} />
      </View>
    </View>
  );
};

export default HomeScreen;

create further files for login Screens/Login/Login.js

import {
  View,
  Text,
  Alert,
  TouchableOpacity,
  Image,
  TextInput,
  ScrollView,
  SafeAreaView,
  StatusBar,
  StyleSheet,
} from 'react-native';
import React, {useState} from 'react';
const Login = ({navigation}) => {
  const [userName, setUserName] = useState('');

  const [password, setPassword] = useState('');

 const submit = () => {
    axios
      .post(your api here', {
        username: username,
        password: password, 
      })
      .then(async res => {
        await AsyncStorage.setItem('userToken', JSON.stringify(res.data));
        navigation.navigate('Home');
      })
      .catch(error => alert());
  };
  return (
    <SafeAreaView style={styles.container}>
      <ScrollView style={styles.scrollView}>
        <View style={styles.mainContainer}>
          <View style={styles.mainImage}>
            <Text style={styles.image}>Log in</Text>
          </View>
          <Text style={styles.mainHeader}>Login Form</Text>
          <Text style={styles.description}>
            This is first test for login Form
          </Text>
          <View style={styles.input}>
            <Text style={styles.label}>Enter Your Name </Text>
            <TextInput
              value={userName}
              onChangeText={actual => setUserName(actual)}
              style={styles.inputStyle}
              autoCapitalize="none"
              autoCorrect={false}
            />
          </View>
          <View style={styles.input}>
            <Text style={styles.label}>Enter Your Password</Text>
            <TextInput
              value={password}
              onChangeText={actual => setPassword(actual)}
              style={styles.inputStyle}
              autoCapitalize="none"
              autoCorrect={false}
              secureTextEntry={true}
            />
          </View>

          <TouchableOpacity onPress={() => submit()} style={styles.buttonStyle}>
            <Text style={styles.btn}>Login</Text>
          </TouchableOpacity>
        </View>
      </ScrollView>
    </SafeAreaView>
  );
};
const styles = StyleSheet.create({
  container: {
    flex: 1,
    paddingTop: StatusBar.currentHeight,
  },
  scrollView: {
    marginHorizontal: 20,
  },
  mainContainer: {
    display: 'flex',
    justifyContent: 'center',
    alignItems: 'center',
    height: '100%',
    paddingHorizontal: 10,
    paddingTop: 30,
    backgroundColor: '#fff',
  },
  mainHeader: {
    fontSize: 25,
    color: '#344055',
    fontWeight: '500',
    paddingTop: 20,
    paddingBottom: 15,
    textTransform: 'capitalize',
    fontFamily: 'regular',
  },
  mainImage: {
    display: 'flex',
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  image: {
    width: 85,
    height: 85,
  },
  description: {
    fontSize: 20,
    color: '#7d7d7d',
    paddingBottom: 20,
    lineHeight: 25,
    fontFamily: 'regular',
  },
  input: {
    marginTop: 20,
  },
  label: {
    fontSize: 18,
    color: '#7d7d7d',
    marginTop: 5,
    marginBottom: 5,
    lineHeight: 25,
    fontFamily: 'regular',
  },
  inputStyle: {
    width: 280,
    borderWidth: 1,
    borderBottomColor: 'rgb(0,0,0.3',
    paddingHorizontal: 15,
    padddingVertical: 7,
    borderRadius: 1,
    fontFamily: 'regular',
    fontSize: 18,
  },
  checkbox: {alignSelf: 'center'},
  wrapper: {},
  buttonStyle: {
    marginTop: 10,
    backgroundColor: 'blue',
    justifyContent: 'center',
    width: '100%',
    height: 40,
    borderRadius: 5,
    marginBottom: 10,
  },
  btn: {
    fontSize: 22,
    textAlign: 'center',
    color: 'white',
  },
});

export default Login;

Here we are saving the JWT in AsyncStorage

Now create a custom Hook for Hooks/Auth.js file like so

import React, {useEffect, useState} from 'react';
import AsyncStorage from '@react-native-async-storage/async-storage';
import {useNavigation} from '@react-navigation/native';
const useAuth = () => {
  const navigation = useNavigation();

  const [data, setData] = useState();
  const readData = async () => {
    try {
      const value = await AsyncStorage.getItem('userToken');

      if (value !== null) {
        const parseData = JSON.parse(value);

        setData(parseData);
      } else {
        navigation.navigate('SignIn');
 
      }
    } catch (e) {
      alert('Failed to fetch the input from storage');
    }
  };
 
  useEffect(() => {
    readData();
  }, []);
  return data;
};

export default useAuth;

Lastly only call the useAuth hook where you want to apply authentication

Like we are applying in Home.js file

const HomeScreen = ({navigation}) => {
  useAuth();
 const logOutPress = async () => {
    try {
      await AsyncStorage.clear();
      alert('Storage successfully cleared!');
         navigation.navigate('SignIn');
    } catch (e) {
      alert('Failed to clear the async storage.');
    }
  };

  return (
    <View
      style={{
        display: 'flex',
        justifyContent: 'center',
        alignItems: 'center',
        height: '100%',
        backgroundColor: '#FFFFFF',
        width: '100%',
      }}>
      <Text style={{color: '#333'}}>HomeScreen</Text>
      <View style={{marginTop: 10}}>
        <Button title="logOutScreen" onPress={ logOutPress} />
      </View>
    </View>
  );
};

export default HomeScreen;

And for logout we clear the AsyncStorage JWT and when we clear it return us to login Page.

Happy coding!