How to Use @Post Decorator in NestJS: Simple Guide

In NestJS, use the @Post decorator to define a route handler for HTTP POST requests inside a controller class. It marks a method to respond when a client sends a POST request to the specified path. You can optionally provide a route path inside @Post('path') to customize the endpoint.

Syntax

The @Post decorator is used above a controller method to handle HTTP POST requests. You can use it with or without a route path.

• @Post(): Handles POST requests to the controller's base route.
• @Post('custom-path'): Handles POST requests to the controller's base route plus /custom-path.

The method below the decorator will execute when a matching POST request is received.

typescript

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

@Controller('items')
export class ItemsController {
  @Post()
  createItem() {
    // logic to create an item
  }

  @Post('special')
  createSpecialItem() {
    // logic for special item
  }
}

Example

This example shows a simple NestJS controller with a @Post method that accepts data and returns a confirmation message. It demonstrates how to handle POST requests at the base route.

typescript

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

@Controller('products')
export class ProductsController {
  @Post()
  createProduct(@Body() productData: { name: string; price: number }) {
    return {
      message: `Product '${productData.name}' created with price $${productData.price}`,
    };
  }
}

Output

{"message":"Product 'Book' created with price $15"}

Common Pitfalls

Common mistakes when using @Post include:

• Forgetting to add @Body() to access POST request data, resulting in undefined input.
• Not specifying a route path when multiple POST handlers exist, causing route conflicts.
• Using @Post outside a controller class, which will not work.

Always ensure your method parameters match the expected decorators and your controller is properly registered.

typescript

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

@Controller('users')
export class UsersController {
  // Wrong: missing @Body() decorator
  @Post()
  createUser(userData: any) {
    return userData; // userData will be undefined
  }

  // Correct usage
  @Post('register')
  registerUser(@Body() userData: any) {
    return userData; // userData contains POST body
  }
}

Quick Reference

Summary tips for using @Post in NestJS:

• Use @Post() to handle POST requests at the controller's base path.
• Add a string inside @Post('path') to handle POST requests at a sub-route.
• Use @Body() to access the POST request body data.
• Ensure your controller is decorated with @Controller() and registered in a module.

Key Takeaways

Use @Post decorator above controller methods to handle HTTP POST requests.

Optionally provide a route path inside @Post('path') to customize the endpoint.

Use @Body() to access data sent in the POST request body.

Always define @Post methods inside classes decorated with @Controller.

Avoid route conflicts by specifying unique paths for multiple POST handlers.