Project structure overview in React Native - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the purpose of the 'src' folder

In a React Native project, what is the main purpose of the 'src' folder?

A To store all source code files like components, screens, and utilities

B To keep configuration files like package.json and babel.config.js

C To hold compiled JavaScript files for production

D To store image assets and fonts only

💡 Hint

Think about where you write your app's main code.

The 'src' folder is used to organize all source code files such as components, screens, and helper utilities. Configuration files and assets are usually stored elsewhere.

❓ ui_behavior

intermediate

Effect of placing components outside 'src' folder

What happens if you place React Native components outside the 'src' folder in a typical project?

A The app will not run because components must be inside 'src'

B The app runs fine but it becomes harder to organize and maintain code

C The app will crash on startup due to missing components

D The components will automatically be ignored during build

💡 Hint

Think about code organization and build process.

React Native does not require components to be inside 'src', but placing them outside can make the project messy and harder to maintain.

❓ lifecycle

advanced

Role of 'App.js' in project structure

In a React Native project, what is the role of the 'App.js' file in the project structure?

A It is the main entry point that registers the root component for the app

B It contains only styles and no functional code

C It is used to configure native Android and iOS settings

D It stores environment variables for the app

💡 Hint

Think about what starts the app when it launches.

'App.js' is the main file that defines the root React component and is registered to start the app.

❓ navigation

advanced

Where to place navigation files in project structure

Where is the best place to put navigation-related files in a React Native project?

A In the root project folder alongside package.json

B Mixed directly inside the 'components' folder

C Inside a dedicated 'navigation' folder within 'src' for clear separation

D Inside the 'assets' folder with images

💡 Hint

Think about keeping related files organized.

Navigation files are best kept in their own folder inside 'src' to keep the project organized and maintainable.

🔧 Debug

expert

Identifying cause of 'module not found' error

You moved a component file from 'src/components' to 'components' at the root level but now get a 'module not found' error when importing it. What is the most likely cause?

A The Metro bundler cache was cleared accidentally

B React Native does not allow components outside 'src'

C The moved file lost its file extension during move

D The import path in other files was not updated to reflect the new location

💡 Hint

Check import statements after moving files.

When moving files, import paths must be updated to the new location. Otherwise, the bundler cannot find the module.

Practice

1. In a typical React Native project, where should you place your main app code for better organization?

easy

A. Inside the android folder

B. Directly in the root folder

C. Inside a folder named src

D. Inside the ios folder

Solution

1. Step 1: Understand folder roles

   The android and ios folders contain platform-specific native code, not app logic.

2. Step 2: Identify app code location

   App code is best organized inside a src folder to keep it separate and clear.

3. Final Answer:

   Inside a folder named src -> Option C

4. Quick Check:

   App code = src folder [OK]

Hint: App code goes in src folder, not platform folders [OK]

Common Mistakes:

• Putting app code inside android or ios folders
• Keeping all code in the root folder without organization

2. Which of the following is the correct folder name for platform-specific Android code in a React Native project?

easy

A. android

B. android_src

C. AndroidCode

D. androidApp

Solution

1. Step 1: Recall standard folder names

   React Native uses android as the folder name for Android platform code by default.

2. Step 2: Compare options

   Only android matches the exact folder name used by React Native.

3. Final Answer:

   android -> Option A

4. Quick Check:

   Android folder = android [OK]

Hint: Platform folders are named exactly android and ios [OK]

Common Mistakes:

• Using camelCase or underscores in platform folder names
• Confusing app code folder with platform folders

3. Given this React Native project structure:

myApp/
├── android/
├── ios/
├── src/
│   └── App.js
└── package.json

Where will the main app component be located?

medium

A. Directly in the root folder

B. Inside ios folder

C. Inside android folder

D. Inside src folder

Solution

1. Step 1: Analyze folder contents

   The src folder contains App.js, which is the main app component file.

2. Step 2: Understand platform folders

   The android and ios folders hold native code, not React Native components.

3. Final Answer:

   Inside src folder -> Option D

4. Quick Check:

   Main app component = src/App.js [OK]

Hint: Main app code lives in src, not platform folders [OK]

Common Mistakes:

• Assuming main app code is inside android or ios
• Looking for app code in the root folder

4. You see this error when running your React Native app: "Cannot find module './App'". Your project structure is:

myApp/
├── android/
├── ios/
├── app/
│   └── App.js
└── package.json

What is the likely cause?

medium

A. The package.json file is corrupted

B. The app code is inside app folder but should be in src

C. The android folder is missing App.js

D. The ios folder is empty

Solution

1. Step 1: Identify folder mismatch

   The app code is in app folder, but React Native expects it in src or root by default.

2. Step 2: Understand module resolution

   Since the code is not where expected, the bundler cannot find ./App module.

3. Final Answer:

   App code is inside app folder but should be in src -> Option B

4. Quick Check:

   App folder mismatch = module not found error [OK]

Hint: App code folder must match import paths exactly [OK]

Common Mistakes:

• Ignoring folder naming conventions
• Assuming platform folders hold app code
• Not checking import paths

5. You want to add a new feature to your React Native app. Which project structure change helps keep your code organized and maintainable?

hard

A. Create a new folder inside src for the feature components

B. Add all new files directly to the root folder

C. Put new feature files inside the android folder

D. Mix new feature files with existing files in ios folder

Solution

1. Step 1: Understand best practices for organization

   Keeping feature code inside src in dedicated folders helps maintain clarity and separation.

2. Step 2: Avoid mixing platform and app code

   Platform folders android and ios are for native code, not React Native components.

3. Final Answer:

   Create a new folder inside src for the feature components -> Option A

4. Quick Check:

   Organize features inside src for maintainability [OK]

Hint: Keep features inside src in separate folders [OK]

Common Mistakes:

• Adding app code to platform folders
• Cluttering root folder with many files
• Not grouping related files