JSON response parsing in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JSON in the context of mobile app development?

JSON stands for JavaScript Object Notation. It is a simple text format used to exchange data between a server and a mobile app in a way that is easy to read and write.

beginner

How do you parse a JSON response in React Native?

You use the built-in JavaScript method JSON.parse() to convert a JSON string into a JavaScript object that your app can use.

beginner

What React Native function is commonly used to fetch JSON data from a server?

The fetch() function is used to make network requests. It returns a promise that resolves to a response object, which you can then parse as JSON.

intermediate

Why should you handle errors when parsing JSON responses?

Because the server might send invalid JSON or the network request might fail. Handling errors prevents the app from crashing and allows showing friendly messages to users.

beginner

What is the typical structure of a JSON response from a server?

A JSON response usually contains key-value pairs inside curly braces { }, where keys are strings and values can be strings, numbers, arrays, or other objects.

Which method converts a JSON string into a JavaScript object in React Native?

A parseJSON()

B JSON.stringify()

C JSON.parse()

D fetch()

JSON.parse() takes a JSON string and turns it into a JavaScript object.

What does the fetch() function return when called in React Native?

A A JSON object

B A promise resolving to a response

C An error

D A string

fetch() returns a promise that resolves to a response object, which you can then parse.

If the JSON response is invalid, what should your app do?

A Handle the error gracefully

B Ignore the response

C Crash immediately

D Reload the app

Handling errors gracefully prevents crashes and improves user experience.

Which of these is a valid JSON value?

A "Hello World"

B undefined

C function() {}

D NaN

JSON values can be strings like "Hello World", but not functions or undefined.

What is the first step to parse JSON from a fetch response?

A Call fetch.json()

B Call JSON.parse() directly on fetch

C Call JSON.stringify()

D Call response.json()

You call response.json() to get a promise that resolves to the parsed JSON object.

Explain how to fetch and parse JSON data in a React Native app.

Think about the steps from requesting data to using it in your app.

Describe why error handling is important when parsing JSON responses.

Consider what happens if the data is not what you expect.