####What is Node.js? Node.js is a server-side platform built on Google Chrome's JavaScript Engine (V8 Engine).

####Where to use Node.js

• I/O Bound Applications
• JSON API Based Applications
• Single Page Applications

Installing Node.js

From Binaries: Download the Node.js Binaries from Official Download Page Go To Downloads page

On Ubuntu:

sudo apt-get install -y nodejs```

Creating a Simple Node.js Application

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Initializing a Node.js Application

Make a New Folder for your Node.js Application and cd into that new folder using Terminal (CMD)

mkdir SampleNodeJSApp
cd SampleNodeJSApp/

Initialize a Node.js Application using NPM package manager

npm init

Now you will be asked a series of questions. You need to answer according to your project.

• name : Name of your project in lowercase
• version : Version of your project.
• description : Description about your Project
• entry point : Defines entry point for App. Usually index.js or server.js
• test command : Command to execute test suite
• git repository : Link of Git repo
• keywords : Keywords which describes your application best.
• author : Your Name
• license : License

Now you will be presented a generated package.json file to review.

Sample Directory Structure for Node.js App

• assets : Contains all client-side assets that require compilation
  • css : Contains all your LESS/Stylus style-sheets
  • js : Contains your client-side CoffeeScript/ES6 files
• dist : Contains all compiled server-side scripts
• LICENSE : License file
• package.json : file contains meta data about your app or module
• public : Contains your static files that are not handled by any compilers
• README.md : Read Me file
• routes.js : Contains all routes
• server.js : Entry Point
• src : Contains all server-side scripts
  • controller : Contains all Controllers
  • middleware : Contains all middleware scripts
  • model : Contains Models if
• test : Contains all unit testing scripts ( implemented using a testing-framework of your choice )
• views : Contains all your express views ( pug,handlebars, ejs or any other templating engine )

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Some Frameworks Available for Node.js

1. Express.js : a minimalist framework for building a host of web and mobile applications as well as application programming interfaces (APIs).
2. Hapi.js : a powerful Node.js web framework for building application program interfaces (APIs) and other software applications.
3. Socket.io : a Node.js server framework for building real-time web applications
4. Meteor : an open-source, model-view controller (MVC) framework for building websites and web/mobile applications.
5. Sails.js : Sails.js is one of the most popular real-time frameworks around for building Node.js applications. Sails.js offers a model-view controller (MVC) pattern for implementing data-driven application programming interfaces (APIs).

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Some of the Databases that can be used as our app's backend

1. MongoDB : a free and open-source cross-platform document-oriented database program
2. MYSQL : an open-source relational database management system (RDBMS).
3. PostgreSQL : an object-relational database (ORDBMS)

There are hundreds of NoSQL Databases available that can be integrated with Node.js. Finding one for your application type is your responsibility :p.

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To Proceed with the sample app I'll choose Express.js and MongoDB

Installing Express.js

npm install express --save

--save option will add express to package.json

Assuming MongoDB installed on your system If not follow this link

Installing MongoDB driver

npm install mongodb --save

We will be creating a simple user authentication system using passport.js

Add passport and passport-local dependencies to package.json

"passport": "~0.2.0",
"passport-local": "~1.0.0"

We need some other dependencies too.Finally your dependencies should look like this

"dependencies": {
        "bcrypt-nodejs": "latest",
        "body-parser": "^1.12.4",
        "connect-flash": "^0.1.1",
        "cookie-parser": "^1.3.5",
        "cookie-session": "^1.1.0",
        "crypto": "^0.0.3",
        "express": "^4.12.4",
        "express-handlebars": "^3.0.0",
        "express-validator": "^2.10.0",
        "mongodb": "^2.2.22",
        "mongoose": "^4.8.1",
        "morgan": "^1.7.0",
        "passport": "^0.2.2",
        "passport-local": "^1.0.0",
        "serve-static": "^1.9.3"
    }

Now we need to choose a templating engine for our Node.js app

Few Popular Choices will be

• Handlebars
• EJS
• Pug
• dust.js
• Mustache.js

Personally I would go for Handlebars. Because it is similar to HTML. It is upto you to choose a Templating engine. I recommend you to go through each of these templating engines and choose one that suits you.

Or you can use AngularJS , ReactJS or Something like VueJS for the frontend

Some Additional Modules used in Sample Application

• Mongoose : Mongoose provides a straight-forward, schema-based solution to model your application data.
• Morgan : HTTP request logger middleware for node.js

Let's get down to Business

First we need to define a User model for our application using Mongoose. ( or not use Mongoose at all. Read more about this issue )

<script src="https://gist.github.com/prabod/7e8e52624c3d6fecac89d8b6cdd6dd14.js"></script>

I have implemented only local registration part. you can refer passport.js website to know more about social media logins.

Now we can implement passport.js login and signup strategies

<script src="https://gist.github.com/prabod/ea6561b6837b44b21b8b11ae87035283.js"></script>

Routes will look like this

<script src="https://gist.github.com/prabod/0d20b644ad65fa92022b611b04dbaf2a.js"></script>

Our Application's Entry Point Server.js will look like this

<script src="https://gist.github.com/prabod/70fa629ee9d9fce4de517ed8872e720b.js"></script>

Final Output

Final Folder Structure

You can find the source to this Sample Application Here ###GITHUB REPOSITORY

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Guide to setup

1. Fork this Repo Fork
2. Clone Forked Repo to your local machine git clone https://github.com/YOURUSERNAME/Sample-Node.js-Application.git
3. Install dependencies npm install
4. Start Application npm start

Now you can build your app on top of this sample application