Getting started with nodeJS

nodejs_gettingstarted.md

How to get started with nodeJS

• How to get started with nodeJS
  • Context
  • Requirements
  • Start the first project
    • Node modules
      • Adding modules
    • Hello World
    • Directory structure

Context

• Tested on macOS
• Brew repository needs to be installed
• Recommended editor for smaller nodejs projects: Visual Studio Code or Atom and for larger projects WebStorm.

Requirements

Install node and npm. Npm will be needed for installing and managing node modules.

brew install node npm

Start the first project

Generate a package.json for the node project:

mkdir my-test-project
cd my-test-project/
npm init

Now enter the informations about the project. After that a package.json file should be generated:

macbookpro:my-test-project phil$ cat package.json
{
  "name": "my-test-project",
  "version": "1.0.0",
  "description": "My little test project",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Philip Schmid",
  "license": "MIT"
}

This file is responsible for the node js application module dependency management and storing some application specific information.

Node modules

Basically the easiest way to get new node modules is installing them via npm from the npmjs registery. In this example we are gonna install a module called express (a minimalist web framework for nodejs):

npm install express --save

--save is key! With this parameter npm adds the module name and version to the package.json file. This ensures, that the nodejs application dependencies can easily be installed with npm install in the future.

For the understanding:

• Each nodejs application needs an own package.json file which spcifies its dependencies.
• npm install searches in an incremental way for node module dependencies specified in the package.json file, which are currently unmet.
• The command npm install downloads the modules to the relative path ./node_modules. This subfolder should be excluded/ignored from any SCM system.
• Its possible to save node modules globaly on the system using the "-g" parameter (e.g. npm install MODUL-NAME -g). However, this is usually not recommended.

Adding modules

The real value of nodejs are the thousands of provided modules which can be used for free. To install and automatically add the module to the packages.json file, use the following command:

npm install MODUL-NAME --save

Now in the index.js the installed module can be used:

const xy = require('MODUL-NAME');

Hello World

Create an entry point for the node js application called index.js. Content:

const express = require('express')
const http = require('http')
const app = express()

app.get('/', function (req, res) {
  res.send('Hello World!')
})

const appPort = 8080;
http.createServer(app).listen(appPort);
console.log('My little test project is listening on port 8080.')

Directory structure

Nodejs doesn't require a specific directory structure. Usually its common to use a structure something like this:

• /models contains all your ORM models (called Schemas in mongoose)
• /views contains your view-templates (using any templating language supported in express)
• /public contains all static content (images, style-sheets, client-side JavaScript)
• /assets/images contains image files
• /assets/pdf contains static pdf files
• /css contains style sheets (or compiled output by a css engine)
• /js contains client side JavaScript
• /controllers contain all your express routes, separated by module/area of your application (note: when using the bootstrapping functionality of express, this folder is called /routes)

Source: stackoverflow.com