Request body in NestJS - Mini Project: Build & Apply

Handling Request Body in NestJS

📖 Scenario: You are building a simple NestJS API to receive user data from a client. The client will send user information in the request body, and your API will process it.

🎯 Goal: Learn how to access and use the request body in a NestJS controller to handle incoming data.

📋 What You'll Learn

Create a controller named UserController

Create a POST route /users in UserController

Use the @Body() decorator to access the request body

Define a DTO class CreateUserDto with name and age properties

Return the received user data from the controller method

💡 Why This Matters

🌍 Real World

APIs often receive data from clients in the request body. Handling this data correctly is essential for creating functional web services.

💼 Career

Understanding how to access and use request body data in NestJS is a fundamental skill for backend developers working with Node.js frameworks.

1

Create the UserController and initial POST method

Create a class called UserController with a method createUser decorated with @Post('users'). Import Controller and Post from @nestjs/common.

NestJS

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

@Controller()
export class UserController {
  // Your code here
}

Need a hint?

Use @Controller() above the class and @Post('users') above the method.

2

Create the CreateUserDto class

Create a class called CreateUserDto with two properties: name of type string and age of type number.

NestJS

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

class CreateUserDto {
  // Your code here
}

@Controller()
export class UserController {
  @Post('users')
  createUser() {
    // Your code here
  }
}

Need a hint?

Define the class with the two properties exactly as name: string; and age: number;.

3

Use @Body() to access the request body

In the createUser method, add a parameter called userData decorated with @Body() and typed as CreateUserDto. Import Body from @nestjs/common.

NestJS

import { Controller, Post, Body } from '@nestjs/common';

class CreateUserDto {
  name: string;
  age: number;
}

@Controller()
export class UserController {
  @Post('users')
  createUser(/* Your code here */) {
    // Your code here
  }
}

Need a hint?

Use @Body() before the parameter and type it as CreateUserDto.

4

Return the received user data

Complete the createUser method by returning the userData parameter.

NestJS

import { Controller, Post, Body } from '@nestjs/common';

class CreateUserDto {
  name: string;
  age: number;
}

@Controller()
export class UserController {
  @Post('users')
  createUser(@Body() userData: CreateUserDto) {
    // Return userData here
  }
}

Need a hint?

Simply return the userData parameter from the method.