Nest.js is a new framework for Node.js.

Core basics: Understand the basic Building blocks of Nest applications.

Build the project

# npm
npm i -g @nestjs/cli
# yarn
yarn global add @nestjs/cli

nest new project-nest
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Running the above command creates the project-nest project directory, installs node_modules and some other boilerplate files, and creates a SRC directory.

Building a project using the Nest CLI creates an initial project structure. But it’s recommended: keep each module in its own dedicated directory.

# Initial project structureD.s │ ├─ App.Controll.js │ ├─ App.Controll.js App. The module. Which s │ ├ ─ ─ app. The module. The js │ ├ ─ ─ app. Module. Js. Map │ ├ ─ ─ app. Service. Which s │ ├ ─ ─ app. Service. Js │ ├ ─ ─ App. Service. Js. Map │ ├ ─ ─ the main, which s │ ├ ─ ─ the main, js │ ├ ─ ─ the main, js. Map │ └ ─ ─ tsconfig. Build. Tsbuildinfo ├ ─ ─ nest - cli. Json ├── Package.json ├─ ├.md ├─ SRC │ ├─ App.Controller. Spec App. The module. Ts │ ├ ─ ─ app. Service. The ts │ └ ─ ─ main. Ts ├ ─ ─test│ ├─ ├─ ├─ ├─ ├.class.txt, ├─ ├.class.txt, ├─ ├.class.txt, ├─ ├.class.txt, ├─ ├.class.txt, ├─ ├.class.txt, ├─ ├.class.txtCopy the code

The core file

├─ SRC │ ├─ App.Controller.spec.tsUnit test sample for base controller│ ├ ─ ─ app. Controller. TsExample of a basic controller with a single route│ ├ ─ ─ app. The module. Ts# The root module of the application│ ├ ─ ─ app. Service. TsBasic service with a single method│ └ ─ ─ the main ts# application entry file
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Main. ts uses NestFactory to create the Nest application instance.

/ * * *@description: application entry file *@update: the 2021-09-07 21:12:01 *@author: Ada.H
*/

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

async function bootstrap() {
  // Create a Nest application instance app using the NestFactory core class
  The create() method returns an object that implements the INestApplication interface
  const app = await NestFactory.create(AppModule); 
  
  // Start HTTP server
  await app.listen(3000);
}

bootstrap();
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Platform independent

Nest is intended to be a platform-agnostic framework, and any Node HTTP framework can be used after the adapter is created. There are two HTTP platforms that support out-of-the-box support: Express (the default) and Fastify.

// When the type is passed to the nestFactory.create () function, the app object will have functions specific to that particular platform.
const app = await NestFactory.create<NestExpressApplication>(AppModule);
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Note: You do not need to specify a type unless you really want to access the underlying platform API.