Project scaffolding in NestJS - Mini Project: Build & Apply

NestJS Project Scaffolding

📖 Scenario: You are starting a new backend project for a simple task management app. You want to set up the basic NestJS project structure to organize your code well.

🎯 Goal: Build the initial NestJS project scaffolding with a root module, a controller, and a service to prepare for adding task management features.

📋 What You'll Learn

Create a root module named AppModule

Create a controller named AppController

Create a service named AppService

Connect the controller and service in the module

Use NestJS decorators properly for module, controller, and service

💡 Why This Matters

🌍 Real World

Setting up a clean NestJS project structure is the first step in building scalable backend applications like task managers, blogs, or APIs.

💼 Career

Understanding NestJS project scaffolding is essential for backend developers working with modern Node.js frameworks in professional environments.

1

Create the root module

Create a class called AppModule and decorate it with @Module from @nestjs/common. For now, leave the imports, controllers, and providers arrays empty.

NestJS

import { Module } from '@nestjs/common';

// Your code here

Hint

Use @Module decorator with empty arrays for imports, controllers, and providers.

2

Create the controller

Create a class called AppController and decorate it with @Controller() from @nestjs/common. For now, leave the class body empty.

NestJS

import { Controller } from '@nestjs/common';

// Your code here

Hint

Use @Controller() decorator on the AppController class.

3

Create the service

Create a class called AppService and decorate it with @Injectable() from @nestjs/common. Leave the class body empty for now.

NestJS

import { Injectable } from '@nestjs/common';

// Your code here

Hint

Use @Injectable() decorator on the AppService class.

4

Connect controller and service in the module

Update the @Module decorator in AppModule to include AppController in the controllers array and AppService in the providers array.

NestJS

import { Module } from '@nestjs/common';
import { Controller } from '@nestjs/common';
import { Injectable } from '@nestjs/common';

// Your code here

Hint

Put AppController inside controllers and AppService inside providers in the @Module decorator.

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