AsyncStorage for key-value in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is AsyncStorage in React Native?

AsyncStorage is a simple, unencrypted, asynchronous, persistent, key-value storage system for React Native apps. It lets you save data locally on the device.

beginner

How do you save a value with AsyncStorage?

Use AsyncStorage.setItem(key, value) to save a string value under a key. It returns a Promise that resolves when the data is saved.

beginner

How do you read a value from AsyncStorage?

Use AsyncStorage.getItem(key) to get the value stored under the key. It returns a Promise that resolves to the string value or null if not found.

intermediate

Why is AsyncStorage asynchronous?

AsyncStorage is asynchronous to avoid blocking the app’s user interface while reading or writing data, keeping the app smooth and responsive.

intermediate

Can AsyncStorage store objects directly?

No, AsyncStorage stores only strings. To save objects, convert them to strings using JSON.stringify before saving, and parse them back with JSON.parse when reading.

Which method saves data in AsyncStorage?

A getItem

B setItem

C removeItem

D clear

setItem is used to save a key-value pair in AsyncStorage.

What type of data does AsyncStorage store?

A Only strings

B Only numbers

C Objects directly

D Binary files

AsyncStorage stores only strings. Objects must be converted to strings first.

Why should AsyncStorage operations be asynchronous?

A To speed up network calls

B To save battery

C To encrypt data

D To keep the app responsive

AsyncStorage is asynchronous to avoid blocking the UI thread and keep the app smooth.

How do you retrieve a value from AsyncStorage?

A getItem(key)

B setItem(key)

C fetchItem(key)

D loadItem(key)

getItem(key) returns the stored string value for the given key.

What should you do before saving an object in AsyncStorage?

A Encrypt it

B Compress it

C Convert it to a string with JSON.stringify

D Convert it to a number

Objects must be converted to strings using JSON.stringify before saving.

Explain how to save and retrieve a user name using AsyncStorage in React Native.

Think about saving a string under a key and reading it back asynchronously.

Describe why AsyncStorage uses asynchronous methods and how that benefits app performance.

Consider what happens if storage was synchronous and how it affects the app.