CLI

NestJS CLI

When to Use This Skill

Use this skill when:

• Creating new NestJS projects
• Generating controllers, services, modules, and other components
• Building and bundling applications
• Working with monorepo/workspace structures
• Running development servers
• Managing project configuration
• Creating libraries for shared code

What is the NestJS CLI?

The NestJS CLI is a command-line interface tool that helps you initialize, develop, and maintain NestJS applications. It provides generators for components, supports workspaces, and handles build configurations.

Installation

Global Installation

npm install -g @nestjs/cli

Using npx

npx @nestjs/cli new my-project

Basic Commands

Create New Project

nest new project-name

Options:

• --strict - TypeScript strict mode
• --package-manager [npm|yarn|pnpm] - Package manager to use
• --language [TS|JS] - Programming language
• --skip-git - Skip git repository initialization
• --skip-install - Skip package installation

Example:

nest new my-app --strict --package-manager pnpm

Generate Resources

nest generate <schematic> <name> [options]

Aliases:

nest g <schematic> <name>

Schematics (Generators)

Application

nest generate application <name>

Creates a new application in a monorepo structure.

Module

nest generate module users
nest g mo users

Creates:

• users/users.module.ts

Controller

nest generate controller users
nest g co users

Creates:

• users/users.controller.ts
• users/users.controller.spec.ts

Options:

• --no-spec - Skip test file
• --flat - Don't create a folder

Service

nest generate service users
nest g s users

Creates:

• users/users.service.ts
• users/users.service.spec.ts

Resource (Complete CRUD)

nest generate resource users
nest g res users

Prompts:

• Transport layer (REST API, GraphQL, Microservice, WebSockets)
• Generate CRUD entry points?

Creates:

• Module
• Controller
• Service
• Entity
• DTOs (create, update)
• Test files

Example output for REST API:

users/
├── dto/
│   ├── create-user.dto.ts
│   └── update-user.dto.ts
├── entities/
│   └── user.entity.ts
├── users.controller.ts
├── users.controller.spec.ts
├── users.module.ts
├── users.service.ts
└── users.service.spec.ts

Other Schematics

# Class
nest g class users/dto/create-user

# Interface
nest g interface users/interfaces/user

# Guard
nest g guard auth/guards/jwt

# Interceptor
nest g interceptor common/interceptors/logging

# Pipe
nest g pipe common/pipes/validation

# Filter
nest g filter common/filters/http-exception

# Middleware
nest g middleware common/middleware/logger

# Decorator
nest g decorator auth/decorators/user

# Gateway (WebSocket)
nest g gateway events

# Resolver (GraphQL)
nest g resolver users

# Library
nest g library shared

Schematic Options

Common Options

# Skip test files
nest g service users --no-spec

# Flat structure (no folder)
nest g controller users --flat

# Dry run (preview changes)
nest g module users --dry-run

# Specific path
nest g service users/services/user

# Skip import into module
nest g service users --no-import

Example:

nest g resource products --no-spec --flat

Build Commands

Development Build

nest build

Compiles TypeScript to JavaScript in dist/ folder.

Production Build

nest build --webpack

Options:

• --watch - Watch mode for development
• --webpack - Use webpack for bundling
• --path [path] - Path to tsconfig file
• --config [path] - Path to nest-cli.json

Watch Mode

nest build --watch

Automatically rebuilds on file changes.

Development Commands

Start Application

nest start

Builds and runs the application.

Development Mode (Watch)

nest start --watch

Watches for changes and restarts automatically.

Alias:

npm run start:dev

Debug Mode

nest start --debug

Starts with Node.js inspector for debugging.

Options:

• --debug [port] - Debug on specific port (default: 9229)
• --watch - Watch mode with debugging

Example:

nest start --debug --watch

Workspaces and Monorepo

Create Workspace

nest new my-workspace
cd my-workspace
nest generate app api
nest generate app admin

Structure:

my-workspace/
├── apps/
│   ├── api/
│   └── admin/
├── libs/
├── nest-cli.json
└── package.json

Generate Library

nest generate library shared
nest g lib common

Creates a shared library in libs/ folder.

Usage in apps:

import { SharedModule } from '@app/shared';

Build Specific Application

nest build api
nest build admin

Start Specific Application

nest start api
nest start admin --watch

Project Configuration

nest-cli.json

{
  "$schema": "https://json.schemastore.org/nest-cli",
  "collection": "@nestjs/schematics",
  "sourceRoot": "src",
  "compilerOptions": {
    "deleteOutDir": true,
    "webpack": true,
    "tsConfigPath": "tsconfig.build.json"
  },
  "generateOptions": {
    "spec": false,
    "flat": true
  }
}

Options:

• sourceRoot - Source code root directory
• compilerOptions.deleteOutDir - Delete output directory before build
• compilerOptions.webpack - Use webpack
• generateOptions.spec - Generate test files by default
• generateOptions.flat - Generate without folder

Monorepo Configuration

{
  "projects": {
    "api": {
      "type": "application",
      "root": "apps/api",
      "entryFile": "main",
      "sourceRoot": "apps/api/src",
      "compilerOptions": {
        "tsConfigPath": "apps/api/tsconfig.app.json"
      }
    },
    "shared": {
      "type": "library",
      "root": "libs/shared",
      "entryFile": "index",
      "sourceRoot": "libs/shared/src",
      "compilerOptions": {
        "tsConfigPath": "libs/shared/tsconfig.lib.json"
      }
    }
  }
}

Additional Commands

Info

nest info

Displays information about:

• Installed packages
• Node.js version
• Operating system
• NestJS CLI version

Example output:

 _   _             _      ___  _____  _____  _     _____
| \ | |           | |    |_  |/  ___|/  __ \| |   |_   _|
|  \| |  ___  ___ | |_     | |\ `--. | /  \/| |     | |
| . ` | / _ \/ __|| __|    | | `--. \| |    | |     | |
| |\  ||  __/\__ \| |_ /\__/ //\__/ /| \__/\| |_____| |_
\_| \_/ \___||___/ \__|\____/ \____/  \____/\_____/\___/

[System Information]
OS Version     : macOS
NodeJS Version : v18.12.0
NPM Version    : 8.19.2

[Nest CLI]
Nest CLI Version : 9.1.5

[Nest Platform Information]
platform-express version : 9.2.0
schematics version       : 9.0.3
common version           : 9.2.0
core version            : 9.2.0

Add

nest add @nestjs/swagger

Adds a library with its schematic installation script.

Common libraries:

nest add @nestjs/swagger
nest add @nestjs/graphql
nest add @nestjs/mongoose
nest add @nestjs/typeorm

Complete Workflow Examples

New REST API Project

# Create project
nest new my-api --strict

# Navigate to project
cd my-api

# Generate a complete resource
nest g resource users

# Generate authentication module
nest g module auth
nest g service auth
nest g controller auth
nest g guard auth/guards/jwt

# Start development server
npm run start:dev

Monorepo Setup

# Create workspace
nest new my-workspace

# Add applications
cd my-workspace
nest g app api
nest g app admin

# Add shared library
nest g lib database
nest g lib common

# Generate resources in specific app
nest g resource users --project api
nest g resource products --project admin

# Start specific app
nest start api --watch

GraphQL Project

# Create project
nest new graphql-api

# Add GraphQL
cd graphql-api
nest add @nestjs/graphql @nestjs/apollo

# Generate GraphQL resources
nest g resource users --type graphql-code-first
nest g resource posts --type graphql-code-first

# Start development
npm run start:dev

Microservices Project

# Create workspace
nest new microservices-app

# Generate microservices
cd microservices-app
nest g app auth-service
nest g app user-service
nest g app api-gateway

# Generate shared library
nest g lib shared

# Start services
nest start auth-service --watch
nest start user-service --watch
nest start api-gateway --watch

Best Practices

1. Use generators - Don't create files manually, use CLI generators
2. Consistent structure - Let CLI maintain project structure
3. Use workspaces - For microservices or multiple related apps
4. Shared libraries - Extract common code into libraries
5. Configure defaults - Set generateOptions in nest-cli.json
6. Skip specs when needed - Use --no-spec for DTOs and entities
7. Use resource generator - For complete CRUD modules
8. Dry run first - Test generators with --dry-run
9. Version control - Commit nest-cli.json for team consistency
10. Use absolute imports - Configure path aliases for clean imports

CLI Shortcuts

# Shorten commands with aliases
nest g mo users          # module
nest g co users          # controller
nest g s users           # service
nest g res users         # resource
nest g gu auth/jwt       # guard
nest g in logging        # interceptor
nest g pi validation     # pipe
nest g fi http-exception # filter
nest g mi logger         # middleware
nest g d current-user    # decorator
nest g ga events         # gateway
nest g r users           # resolver

Common Scripts

Add these to package.json:

{
  "scripts": {
    "start": "nest start",
    "start:dev": "nest start --watch",
    "start:debug": "nest start --debug --watch",
    "start:prod": "node dist/main",
    "build": "nest build",
    "format": "prettier --write \"src/**/*.ts\"",
    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
    "test": "jest",
    "test:watch": "jest --watch",
    "test:cov": "jest --coverage",
    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
    "test:e2e": "jest --config ./test/jest-e2e.json"
  }
}

Troubleshooting

CLI Not Found

# Reinstall globally
npm uninstall -g @nestjs/cli
npm install -g @nestjs/cli

# Or use npx
npx @nestjs/cli new my-project

Import Errors in Monorepo

Check tsconfig.json paths:

{
  "compilerOptions": {
    "paths": {
      "@app/shared": ["libs/shared/src"],
      "@app/common": ["libs/common/src"]
    }
  }
}

Build Errors

# Clean build
rm -rf dist
nest build

# Check TypeScript version
npm list typescript