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Async Storage

AsyncStorage is asynchronous and persistent key-value pair storage system. AsyncStorage is suitable for storing small data sets like user profiles, settings, or app state.

Installation​

You can install Async Storage using the follwing npm command:

npx expo install @react-native-async-storage/async-storage

Import the AsyncStorage:

import { AsyncStorage } from '@react-native-async-storage/async-storage';

Save data​

The setItem(key, value) method can be used to save data. This method takes a key-value pair where the key is a string and the value is either a string or a serializable object converted to a string.

note

Value must be string or it should be 'stringified' before saving using JSON.stringify(). For reading you should then use JSON.parse().

handleSave = async () => {
  try {
    await AsyncStorage.setItem('someKey', 'This is the value');
  } catch (error) {
    Alert.alert('Error when saving data');
  }
}

Read data​

The getItem(key) method can be used to read data. That retrieves data from AsyncStorage using the defined key.

handleRead = async () => {
  try {
    let value = await AsyncStorage.getItem('someKey');
  } catch (error) {
    Alert.alert('Error when reading data');
  } 
}

Expo provides also SecureStore that can be used to encrypt and securely store key–value pairs locally on the device (https://docs.expo.dev/versions/latest/sdk/securestore/).