3-React Native for beginners - By Dhanraj Acharya

ecause A remained mounted the whole time. To overcome this, we have to use lifecycle
events provided by react navigation.
v0.3.0
Goals: How to store data locally.
Every native application needs to store data such as user status, logged in status, app configuration etc. We can
use SecureStore, AsyncStorage, SQLite, and Realm. This are most widely and easy to use services.
Realm is very famous and used widely but you have to perform expo eject to use it so we won’t
be discussing it here. But it is useful to know about such tool so you may use it in future.
SecureStore and AsyncStorage both are key-value storage system. The only difference between them is the way they
store the data. SecureStore encrypts the data while AsyncStorage stores it in plain text.
We won’t be using SecureStore or AsyncStorage. We will only use SQLite in our application but I
have mentioned them here because they are very useful and easy to use.
SecureStore
iOS: Values are stored using the keychain services as kSecClassGenericPassword. iOS has the additional option of
being able to set the value's kSecAttrAccessible attribute, which controls when the value is available to be fetched.
Android: Values are stored in SharedPreferences, encrypted with Android's Keystore system.
we can use below methods to manipulate the data.
SecureStore.getItemAsync(key)
SecureStore.setItemAsync(key,value)
SecureStore.deleteItemAsync(key)
For more information, check out official SecureStore docs.
AsyncStorage
It has the similar API as SecureStore. we mainly use below methods,
AsyncStorage.getItem(key)
AsyncStorage.setItem(key, value)
AsyncStorage.removeItem(key)
For more methods, please check the official expo docs.