Why NestJS exists - See It in Action

Understanding Why NestJS Exists

📖 Scenario: You are a developer learning backend frameworks. You want to understand why NestJS was created and what problems it solves compared to plain Node.js or other frameworks.

🎯 Goal: Build a simple NestJS project that shows the basic setup and a simple controller to demonstrate the framework's structure and purpose.

📋 What You'll Learn

Create a basic NestJS application structure

Add a configuration variable for the port number

Create a simple controller with one route

Complete the main application bootstrap code

💡 Why This Matters

🌍 Real World

NestJS is used to build backend servers for web and mobile apps, APIs, and microservices with a clean and maintainable structure.

💼 Career

Many companies use NestJS for scalable Node.js backend development, so understanding why it exists helps in writing better server-side code and working in teams.

1

Create the basic NestJS application structure

Create a NestJS application by importing NestFactory from @nestjs/core and a root module called AppModule as an empty class.

NestJS

import { NestFactory } from '@nestjs/core';

// Create an empty root module called AppModule
class AppModule {}

// Your code here

Need a hint?

Start by importing NestFactory and define an empty class named AppModule.

2

Add a configuration variable for the port number

Add a constant variable called PORT and set it to 3000 to configure the server port.

NestJS

import { NestFactory } from '@nestjs/core';

class AppModule {}

// Define the server port
const PORT = 3000;
// Your code here

Need a hint?

Use const PORT = 3000; to set the port number.

3

Create a simple controller with one route

Create a controller class called AppController with a method getHello that returns the string 'Hello from NestJS!'. Use the @Controller() decorator and @Get() decorator from @nestjs/common.

NestJS

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

class AppModule {}

const PORT = 3000;

// Create AppController with @Controller and @Get decorators
// Your code here

Need a hint?

Use @Controller() above the class and @Get() above the method that returns the greeting string.

4

Complete the main application bootstrap code

Write an async function called bootstrap that creates the NestJS app with NestFactory.create(AppModule), listens on PORT, and call bootstrap() at the end.

NestJS

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

@Controller()
class AppController {
  @Get()
  getHello() {
    return 'Hello from NestJS!';
  }
}

class AppModule {}

const PORT = 3000;

// Write bootstrap function to start the app
// Your code here

Need a hint?

Use an async function to create and start the NestJS app on the port.