Project scaffolding in NestJS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the default folder created for controllers in a new NestJS project?

When you create a new NestJS project using the CLI, which folder is automatically created to hold controller files?

A src/controllers

B src/modules

C src

D crs

💡 Hint

Think about where the CLI places files that handle incoming requests.

The NestJS CLI creates a 'src' folder by default to organize controller files that handle HTTP requests.

📝 Syntax

intermediate

Which command scaffolds a new NestJS project with npm?

Choose the correct command to create a new NestJS project named 'my-app' using npm.

A nestjs new my-app

B nest new my-app

C npm create nest-app my-app

D npm init nest my-app

💡 Hint

The NestJS CLI uses a simple 'nest' command.

The correct command is 'nest new my-app' which uses the Nest CLI to scaffold a new project.

🔧 Debug

advanced

What error occurs if you run 'nest new' without Node.js installed?

If you try to scaffold a new NestJS project using 'nest new project-name' but Node.js is not installed, what error will you see?

A Command 'nest' not found

B SyntaxError: Unexpected token

C Error: Cannot find module 'nestjs'

D TypeError: nest is not a function

💡 Hint

If Node.js is missing, the CLI command itself won't run.

Without Node.js, the system cannot recognize the 'nest' command, resulting in 'Command 'nest' not found'.

❓ state_output

advanced

After scaffolding, what file contains the main application bootstrap code?

In a freshly created NestJS project, which file contains the code that starts the application?

A src/main.ts

B src/app.module.ts

C src/server.js

D src/index.ts

💡 Hint

Look for the file that calls 'NestFactory.create()'.

The 'src/main.ts' file contains the bootstrap function that starts the NestJS application.

🧠 Conceptual

expert

Which option best describes the purpose of the 'app.module.ts' file in NestJS scaffolding?

What is the main role of the 'app.module.ts' file created by the NestJS CLI in a new project?

A It manages database connections and ORM setup automatically

B It contains the main server configuration and HTTP listener setup

C It holds all the environment variables and configuration settings

D It defines the root module that organizes controllers and providers for the app

💡 Hint

Think about how NestJS groups features and services.

The 'app.module.ts' file defines the root module that groups controllers, providers, and imports to organize the app structure.

Practice

1. What is the main purpose of using nest new project-name in NestJS?

easy

A. To create a new NestJS project with a ready-to-use structure

B. To start the NestJS development server

C. To install NestJS dependencies globally

D. To generate a new module inside an existing project

Solution

1. Step 1: Understand the command nest new project-name

   This command is used to create a new NestJS project folder with all necessary files and folders set up.

2. Step 2: Identify the purpose of scaffolding

   Scaffolding means generating a basic project structure automatically to save time and follow best practices.

3. Final Answer:

   To create a new NestJS project with a ready-to-use structure -> Option A

4. Quick Check:

   Project scaffolding = create new project structure [OK]

Hint: Remember: 'nest new' creates a fresh project folder fast [OK]

Common Mistakes:

• Confusing 'nest new' with starting the server
• Thinking it installs global packages only
• Mixing it up with generating modules inside projects

2. Which of the following is the correct syntax to create a new NestJS project named my-app?

easy

A. nest create my-app

B. nest new my-app

C. nest generate project my-app

D. nest init my-app

Solution

1. Step 1: Recall the NestJS CLI command for new projects

   The official command to scaffold a new project is nest new project-name.

2. Step 2: Match the correct syntax

   Among the options, only nest new my-app matches the correct CLI command format.

3. Final Answer:

   nest new my-app -> Option B

4. Quick Check:

   Correct CLI syntax = nest new [OK]

Hint: Use 'nest new' exactly to scaffold projects [OK]

Common Mistakes:

• Using 'nest create' instead of 'nest new'
• Trying 'nest generate project' which is invalid
• Confusing 'nest init' with project creation

3. After running nest new sample-app, which folder structure will you see inside sample-app?

medium

A. src/, node_modules/, package.json, nest-cli.json

B. app/, config/, public/, package-lock.json

C. controllers/, models/, views/, app.js

D. lib/, bin/, config/, README.md

Solution

1. Step 1: Recall default NestJS project folders

   A new NestJS project contains a src/ folder for source code, node_modules/ for dependencies, and config files like package.json and nest-cli.json.

2. Step 2: Compare options with known structure

   src/, node_modules/, package.json, nest-cli.json matches the expected NestJS scaffold structure; others list unrelated folders or files.

3. Final Answer:

   src/, node_modules/, package.json, nest-cli.json -> Option A

4. Quick Check:

   Default NestJS scaffold = src and config files [OK]

Hint: Look for src folder and package.json in new projects [OK]

Common Mistakes:

• Expecting MVC folders like controllers, models, views
• Confusing with frontend project structures
• Looking for app.js which is not used in NestJS

4. You ran nest new myproject but got an error: Command 'nest' not found. What is the most likely fix?

medium

A. Rename the folder to 'nest' before running the command

B. Run nest new inside an existing NestJS project

C. Use npm start instead of nest new

D. Install Nest CLI globally using npm i -g @nestjs/cli

Solution

1. Step 1: Understand the error meaning

   The error means the system does not recognize the nest command, likely because the Nest CLI is not installed globally.

2. Step 2: Identify the correct fix

   Installing the Nest CLI globally with npm i -g @nestjs/cli makes the nest command available anywhere.

3. Final Answer:

   Install Nest CLI globally using npm i -g @nestjs/cli -> Option D

4. Quick Check:

   Missing CLI = install globally [OK]

Hint: Install Nest CLI globally to use 'nest' command [OK]

Common Mistakes:

• Trying to run 'nest new' inside a non-NestJS folder
• Using npm start which runs app, not CLI
• Renaming folders instead of installing CLI

5. You want to create a new NestJS project but customize the package manager to use yarn instead of npm. Which command should you run?

hard

A. nest new myapp --package yarn

B. nest new myapp --use-yarn

C. nest new myapp --package-manager yarn

D. nest new myapp --pm yarn

Solution

1. Step 1: Recall NestJS CLI option for package manager

   The Nest CLI supports the option --package-manager to specify which package manager to use during project creation.

2. Step 2: Match the correct option syntax

   nest new myapp --package-manager yarn uses the correct full option --package-manager yarn. Other options are invalid or incomplete.

3. Final Answer:

   nest new myapp --package-manager yarn -> Option C

4. Quick Check:

   Use --package-manager to set yarn [OK]

Hint: Use --package-manager option to pick yarn or npm [OK]

Common Mistakes:

• Using shorthand or incorrect flags like --pm or --use-yarn
• Assuming default is yarn without specifying
• Trying --package instead of --package-manager