Project structure overview in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the App.js file in a React Native project?

The App.js file is the main entry point of a React Native app. It defines the root component that renders the app's UI and manages navigation or state at the top level.

beginner

What kind of files are usually found in the assets folder?

The assets folder stores static files like images, fonts, and icons that the app uses to display visuals and style.

beginner

Why do React Native projects have a node_modules folder?

The node_modules folder contains all the external libraries and packages installed via npm or yarn that the app depends on.

beginner

What is the role of the package.json file?

The package.json file lists the project’s dependencies, scripts, and metadata like the app name and version. It helps manage the project setup.

beginner

Where do you usually put reusable UI components in a React Native project?

Reusable UI components are typically placed in a components folder to keep the project organized and make components easy to find and reuse.

Which file is the main entry point of a React Native app?

A index.html

B App.js

C main.css

D config.json

App.js is the root component file where the app starts running.

Where should you put images used in your React Native app?

A node_modules folder

B src folder

C components folder

D assets folder

The assets folder is for static files like images and fonts.

What does the node_modules folder contain?

A External libraries and packages

B App source code

C Image files

D Configuration files

node_modules stores all installed packages your app uses.

Which file lists your app’s dependencies and scripts?

A package.json

B App.js

C README.md

D index.js

package.json manages dependencies and scripts for the project.

Where do you keep reusable UI components in a React Native project?

A node_modules folder

B assets folder

C components folder

D config folder

The components folder organizes reusable UI parts.

Describe the main folders and files you find in a React Native project and their purposes.

Think about where code, images, reusable parts, and dependencies are stored.

Explain why organizing your React Native project structure is important for app development.

Consider how a tidy project helps you and others work better.

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