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Introduction

First Steps

In this set of articles you'll learn the core fundamentals of Nest. The main idea is to get familiar with essential Nest application building blocks. You'll build a basic CRUD application which features covers a lot of ground at an introductory level.

Language

We're in love with TypeScript, but above all - we love Node.JS. That's why Nest is compatible with both TypeScript and pure JavaScript. Nest's is taking advantage of latest language features, so to use a framework with simple JavaScript we need a Babel transpiler.

In the articles, we're mostly using TypeScript, but you can always switch the code snippets to the JavaScript version when it contains some TypeScript-specific expressions.

Prerequisites

Please make sure that Node.JS (>= 6.11.0) is installed on your operating system.

Setup

Setting up a new project is quite simple with starter repository. Just make sure that you have NPM installed then use following commands in your OS terminal:

TypeScript

git clone https://github.com/nestjs/typescript-starter.git project
cd project
npm install

JavaScript

git clone https://github.com/nestjs/javascript-starter.git project
cd project
npm install

The project directory will contain several core files inside src directory.

src
└── server.ts
└── modules
    └── app.controller.ts
    └── app.module.ts

Following the convention, newly created modules should be placed inside modules directory.

File	Description
server.ts	The entry file of the application. It uses NestFactory to create the Nest application instance.
app.module.ts	Defines AppModule, the root module of the application.
app.controller.ts	Basic controller example with a single route.

The server.ts includes an async function, which responsibility is to bootstrap our application:

import { NestFactory } from '@nestjs/core';
import { ApplicationModule } from './modules/app.module';

async function bootstrap() {
    const app = await NestFactory.create(ApplicationModule);
    await app.listen(3000);
}

bootstrap();

To create a Nest application instance, we use the NestFactory. The create() method returns an object, which implements the INestApplication interface, and provides a set of usable methods, which are well described in the following guides.

Running Your Application

Once the installation process is completed, you can run the following command to start the HTTP server:

$ npm run start

This command starts the HTTP server on the port defined inside the server.ts file in the src directory. While the application is running, open your browser and navigate to http://localhost:3000/. If everything worked correctly, you should see the Hello world! message.