Set up Development Environment

Overview

You will start with installing the tools necessary to get started. Once your development environment is set up, you can begin with scaffolding an initial application with the NestJS CLI. Throughout this tutorial, you'll modify and extend this starter application to use the SAP Cloud SDK for JavaScript.

In this part of the tutorial, you will do the following:

• Install Node.js and npm.
• Install the Nest CLI.
• Install the Cloud Foundry CLI, cf.
• Scaffold your NestJS application and learn about the project's structure.
• Run the application locally.

Node.js and npm

If you have Node.js and npm installed, skip ahead to the next step. To check the Node.js and npm versions you have installed, run the following commands:

node -v
npm -v

If one of those commands fails, you will have to install Node.js. It is recommended to use the latest LTS version.

Install Nest CLI

You need to have the Nest CLI installed to create a new project. You can install it globally by executing the following command:

npm i -g @nestjs/cli

Cloud Foundry Command Line Interface

You will need the Cloud Foundry CLI (cf) to later deploy your application to the SAP Business Technology Platform. To see whether it is already installed, run the following:

cf -v

If the command fails, you will need to install cf.

You can find installation instructions for all common platforms in the Cloud Foundry documentation. We recommend using a package manager for that. If you are using Chocolatey on Windows, please find the instructions here.

Scaffold an Application

You can now create a new project using the command below:

nest new <project-name>

This will create an application that already contains all the files and configuration you need to use the SAP Cloud SDK for JavaScript. The CLI will ask you to select a package manager. Select "npm". The CLI will then install all the necessary dependencies for the project, so this might take a minute. If everything worked correctly, you should see an output like this:

🚀  Successfully created project <project-name>
👉  Get started with the following commands:

$ cd <project-name>
$ npm run start

Get Familiar With the Project

The project contains the following files and folders:

npm / Project

• package.json: Specifies dependencies, metadata, and user-defined scripts. The application comes with some predefined scripts and dependencies.

TypeScript

• tsconfig.json: Configuration file for TypeScript. This is not needed in the plain JavaScript version.

Local Development

• src/: Source code for the initial application.

Run the Project

To run the application locally, execute the following command:

npm run start:dev

This will start a local server in watch mode so that subsequent changes will automatically trigger a restart of the server. Go to http://localhost:3000 and you should get a "Hello World!" in response. Before continuing with the next part of the tutorial, open src/main.ts and switch the port from 3000 to 8080. This is required as the mock server (covered later) runs on port 3000. The corresponding line should then look like this:

await app.listen(process.env.PORT || 8080);

Final Code Review

In this tutorial, you installed the CLI tools necessary for creating and deploying your application and scaffolded an initial NestJS application.

Here are the code files discussed on this page:

src/main.ts

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

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(process.env.PORT || 8080);
}
bootstrap();

src/app.module.ts

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [],
  controllers: [AppController],
  providers: [AppService]
})
export class AppModule {}

src/app.controller.ts

import { Controller, Get } from '@nestjs/common';
import { AppService } from './app.service';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @Get()
  getHello(): string {
    return this.appService.getHello();
  }
}

src/app.service.ts

import { Injectable } from '@nestjs/common';

@Injectable()
export class AppService {
  getHello(): string {
    return 'Hello World!';
  }
}