NestjsHow-ToBeginner · 3 min read

How to Create Controller in NestJS: Simple Guide

In NestJS, create a controller by defining a class decorated with @Controller() and adding route handlers with decorators like @Get(). This class handles incoming requests and returns responses in your application.

📐

Syntax

A NestJS controller is a class decorated with @Controller(). Inside, methods handle HTTP requests using decorators like @Get(), @Post(), etc. Each method corresponds to a route and returns a response.

Parts explained:

@Controller('path'): Defines the base route path for the controller.
Class: Contains route handler methods.
@Get('subpath'): Handles GET requests to /path/subpath.
Method: Returns data or response for the route.

typescript

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

@Controller('items')
export class ItemsController {
  @Get()
  findAll() {
    return 'This action returns all items';
  }
}

💻

Example

This example shows a simple controller named ProductsController that handles GET requests to /products and returns a list of product names.

typescript

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

@Controller('products')
export class ProductsController {
  @Get()
  getAllProducts() {
    return ['Apple', 'Banana', 'Cherry'];
  }
}

Output

["Apple", "Banana", "Cherry"]

⚠️

Common Pitfalls

Common mistakes when creating controllers include:

Forgetting to add the @Controller() decorator, so NestJS does not recognize the class as a controller.
Not importing the controller in the module's controllers array, so it is not registered.
Using incorrect HTTP method decorators or missing route paths.

Example of a wrong and right way:

typescript

/* Wrong: Missing @Controller decorator */
export class WrongController {
  @Get()
  getData() {
    return 'No controller decorator';
  }
}

/* Right: With @Controller decorator and registered in module */
import { Controller, Get } from '@nestjs/common';

@Controller('right')
export class RightController {
  @Get()
  getData() {
    return 'Controller works';
  }
}

📊

Quick Reference

Decorator	Purpose
@Controller('path')	Defines a controller with base route path
@Get('subpath')	Handles HTTP GET requests
@Post('subpath')	Handles HTTP POST requests
@Put('subpath')	Handles HTTP PUT requests
@Delete('subpath')	Handles HTTP DELETE requests

✅

Key Takeaways

Use @Controller() to define a controller class in NestJS.

Add route handlers with decorators like @Get(), @Post() inside the controller.

Each method in the controller corresponds to an HTTP route and returns a response.

Avoid missing decorators or module registration to prevent your controller from working.