Response handling in NestJS - Mini Project: Build & Apply

Response Handling in NestJS

📖 Scenario: You are building a simple NestJS API that returns user data. You want to control how the response is sent back to the client.

🎯 Goal: Create a NestJS controller that handles a GET request and returns a JSON response with a status code and a message.

📋 What You'll Learn

Create a controller named UsersController

Add a GET route handler method named getUser

Return a JSON object with statusCode and message fields

Use NestJS @Res() decorator to send the response with status 200

💡 Why This Matters

🌍 Real World

APIs often need to send custom responses with specific status codes and messages to clients.

💼 Career

Understanding response handling in NestJS is essential for backend developers building RESTful APIs.

1

Create UsersController with a getUser method

Create a class called UsersController and add a method named getUser inside it.

NestJS

export class UsersController {
  // Define getUser method here
  // Your code here
}

Need a hint?

Use export class UsersController {} and define getUser() inside.

2

Add @Controller and @Get decorators

Add the @Controller('users') decorator above the UsersController class and the @Get() decorator above the getUser method.

NestJS

@Controller('users')
export class UsersController {
  @Get()
  getUser() {
    // Your code here
  }
}

Need a hint?

Import and use @Controller('users') and @Get() decorators.

3

Inject Response object and send JSON response

Add a parameter named res to getUser method with the @Res() decorator. Use res.status(200).json() to send a JSON response with { statusCode: 200, message: 'User data fetched successfully' }.

NestJS

@Controller('users')
export class UsersController {
  @Get()
  getUser(@Res() res) {
    // Your code here
  }
}

Need a hint?

Use @Res() to inject the response object and send JSON with res.status(200).json(...).

4

Import necessary decorators from @nestjs/common

Add import statements for Controller, Get, and Res from @nestjs/common at the top of the file.

NestJS

// Import decorators here

@Controller('users')
export class UsersController {
  @Get()
  getUser(@Res() res) {
    res.status(200).json({ statusCode: 200, message: 'User data fetched successfully' });
  }
}

Need a hint?

Import Controller, Get, and Res from @nestjs/common.