NestJS Persons API

A simple NestJS application that provides CRUD APIs for managing persons with in-memory storage.

Features

• Create Person: Add a new person with name, gender, and date of birth
• Get Person by ID: Retrieve a specific person by their unique ID
• Get All Persons: Retrieve all persons in the system
• Delete Person by ID: Remove a person from the system

Person Schema

Each person has the following properties:

• id: Number (1-1000, auto-generated sequentially)
• name: String (required)
• gender: String (required, must be 'male', 'female', or 'other')
• dateOfBorn: Number (required, birth year between 1900 and current year)

Installation

1. Install dependencies:

npm install

2. Start the application:

npm run start:dev

The application will run on http://localhost:3000

Note: The start:dev command automatically kills any process running on port 3000 before starting to prevent "port already in use" errors.

API Endpoints

1. Create Person

• Method: POST
• URL: /persons
• Body:

{
  "name": "John Doe",
  "gender": "male",
  "dateOfBorn": 1990
}

• Response: Returns the created person with generated numeric ID (1-1000)

2. Get All Persons

• Method: GET
• URL: /persons
• Response: Returns array of all persons

3. Get Person by ID

• Method: GET
• URL: /persons/:id
• Response: Returns the person with specified ID

4. Update Person

• Method: PUT
• URL: /persons/:id
• Body: (All fields are optional)

{
  "name": "Jane Doe",
  "gender": "female",
  "dateOfBorn": 1992
}

• Response: Returns the updated person

5. Delete Person

• Method: DELETE
• URL: /persons/:id
• Response: 204 No Content

Example Usage with curl

Create a person:

curl -X POST http://localhost:3000/persons \
  -H "Content-Type: application/json" \
  -d '{
    "name": "John Doe",
    "gender": "male",
    "dateOfBorn": 1990
  }'

Get all persons:

curl http://localhost:3000/persons

Get person by ID:

curl http://localhost:3000/persons/1

Update a person:

curl -X PUT http://localhost:3000/persons/1 \
  -H "Content-Type: application/json" \
  -d '{
    "name": "John Smith",
    "dateOfBorn": 1991
  }'

Delete a person:

curl -X DELETE http://localhost:3000/persons/1

Data Storage

This application uses persistent file storage with the following features:

• Data is automatically saved to data/persons.json after every create, update, or delete operation
• Data is automatically loaded from the file when the application starts
• Data persists between application restarts - no data loss!
• No database setup is required - uses simple JSON file storage
• The data/ directory is created automatically if it doesn't exist

File Location

• File Path: data/persons.json (in the project root)
• Format: Pretty-printed JSON with proper Date object handling
• Auto-backup: Data is saved immediately after every operation

Development Scripts

• npm run start: Start the application
• npm run start:dev: Start in development mode with auto-reload
• npm run start:debug: Start in debug mode
• npm run build: Build the application
• npm run test: Run tests
• npm run lint: Run linter

Technology Stack

• NestJS (Node.js framework)
• TypeScript
• Class-validator (Input validation)
• UUID (Unique ID generation)
• Express (HTTP server)