7. Data Storage: Local Storage and AsyncStorage

Learning Objectives Define persistent data storage and explain its importance in mobile apps. Differentiate between synchronous (Local Storage) and asynchronous (AsyncStorage) operations. Explain the concept of a key-value pair for storing data. Write code to save a simple string value using AsyncStorage. Write code to retrieve a saved string value using AsyncStorage. Write code to remove a saved value using AsyncStorage. Ever wonder how a game remembers your high score or a to-do list app remembers your tasks even after you close it? 🤔 Let's learn the magic behind it! In this lesson, we'll explore how mobile apps save information directly on your device. We will learn about two common methods, Local Storage and AsyncStorage, and discover how to use them to make...

TermDefinitionExample Persistent StorageA way for an application to save data that remains even after the app is closed or the device is turned off. This is different from a variable, which is cleared from memory when the app closes.Your phone's photo gallery uses persistent storage to keep your pictures safe. Key-Value PairA simple way to store data where each piece of information (the 'value') is given a unique name (the 'key') to find it later. Think of it like a dictionary word and its definition.To store a username, you might use the key 'username' and the value 'gamer123'. Local StorageA type of web storage that allows web apps to store key-value pairs in a web browser. It is synchronous, meaning it blocks other code from running until it...

Saving Data with AsyncStorage await AsyncStorage.setItem('keyName', 'value'); Use this pattern to save a string value. The 'keyName' is the unique identifier you'll use to find the data later, and 'value' is the information you want to store. The `await` keyword is crucial because the operation is asynchronous. Getting Data with AsyncStorage const myValue = await AsyncStorage.getItem('keyName'); Use this pattern to retrieve a previously saved value. You provide the 'keyName' you used to save the data, and it returns the corresponding value. If the key doesn't exist, it returns `null`. Removing Data with AsyncStorage await AsyncStorage.removeItem('keyName'); Use this pattern to delete a sp...