EAS Build (Expo) in React Native - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary purpose of EAS Build in Expo?

Choose the best description of what EAS Build does for a React Native app using Expo.

A It compiles your app in the cloud to create native binaries without needing a local development environment.

B It runs your app directly on a physical device without building any binaries.

C It only helps with debugging JavaScript code inside Expo Go.

D It replaces the need for writing any native code in your app.

💡 Hint

Think about how you get an installable app file from your code.

EAS Build compiles your React Native app in the cloud, producing native app files (like .apk or .ipa) without requiring you to set up native build tools locally.

❓ ui_behavior

intermediate

What happens when you run 'eas build --platform ios' without configuring credentials?

You run the command 'eas build --platform ios' in your project folder but have not set up any Apple credentials. What will EAS Build do?

A It will build the app without signing it, producing an unsigned binary.

B It will fail immediately with a syntax error.

C It will prompt you to log in to your Apple Developer account and help manage credentials automatically.

D It will skip the build and open the Expo Go app instead.

💡 Hint

EAS Build helps manage credentials for you if you don't have them set up.

EAS Build can interactively ask you to log in to your Apple Developer account and handle certificates and profiles automatically to sign your app.

❓ lifecycle

advanced

How does EAS Build integrate with your app's development lifecycle?

Which statement best describes how EAS Build fits into the React Native app development process?

A EAS Build replaces local development and testing, so you only build in the cloud after finishing all coding.

B EAS Build is used to create production-ready binaries after local development and testing are done.

C EAS Build automatically updates your app code on users' devices without submitting to app stores.

D EAS Build is only for debugging and does not produce installable app files.

💡 Hint

Think about when you need to create the final app files for distribution.

Developers write and test code locally or with Expo Go, then use EAS Build to create signed, production-ready app files for app stores or distribution.

❓ navigation

advanced

Which EAS Build command lets you view the status and logs of your current build?

You want to check the progress and details of your ongoing EAS Build. Which command should you use?

A eas build:logs

B eas build:status

C eas build:list

D eas build:view

💡 Hint

Think about which command name suggests showing logs.

The command 'eas build:logs' shows real-time logs and status of your current or past builds.

🔧 Debug

expert

What error will you get if your eas.json file is missing the 'production' profile when running 'eas build'?

You run 'eas build' but your eas.json does not have a 'production' profile defined. What error message will EAS Build show?

A Warning: Using default build profile.

B SyntaxError: Unexpected token in eas.json.

C Error: Missing credentials for build.

D Error: No build profile named 'production' found in eas.json.

💡 Hint

Check the error about missing profiles in configuration files.

EAS Build expects a 'production' profile in eas.json by default. If missing, it errors out saying no such profile found.