Basics of Node.js for MEAN Stack Development

Introduction

• This is just an introduction of Node.js.
• In other words 'N' of the MEAN Stack.
• This is the second part of the series of articles which I will write about the MEAN.
• Here is the first part of this article MEAN Stack Development with MongoDB.

What is Node.js ?

• Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications.
• It uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.
• It's perfect for data-intensive real-time applications that run across distributed devices.

How to Install Node.js on Windows ?

Step 1 :

• Installing Node.js on a Windows machine is a simple task that can be easily accomplished using the standalone installer.
• Just go to Node.js download page and download the right .msi file (32-bit or 64-bit ).
• I have downloaded the 64-bit version.

Step 2 :

• After downloading the installer, just double click it.
• If you get any security dialog boxes, just click on the Run button and the installation wizard should start.
• You will be prompted with an installation screens similar to the following screenshots.

Congratulations !. You have successfully installed the Node.js.

How to Run Node.js ?

Step 1 :

• You have to open the Nods.js Command Line Interface (CLI).
• Just go to the Nods.js installed folder and run the Node application as shown below.

• This will start the Node.js CLI, which will wait for a JavaScript input. 

Step 2 :

• To test the Node.js installation, run the following command on CLI.

          console.log('Node is up and running!');

• Congratulations ! You have just created your fist Node.js application. 

Step 3 :

• To stop the CLI, press CTRL + D

What is  Node Package Manager (NPM) ?

• Node.js is a platform, which means its features and APIs are kept to a minimum.
• To achieve more complex functionality, it uses a module system that allows you to extend the platform.
• The best way to install, update, and remove Node.js modules is using the NPM.
• Conveniently, NPM is installed during the Node.js installation process.

What are the Key  Features of NPM ?

• A registry of packages to browse, download, and install third-party modules.
• A Command Line Interface (CLI) tool to manage local and global packages.

What are the Installation modes on NPM ?

• It is important to remember that NPM has two installation modes.
• Which are Local mode and Global mode.

Local Mode

• The default local mode is used more often and installs the third-party packages in a local node_modules folder placed inside your application folder.
• It has no effect system-wise, and is used to install the packages your application needs, without polluting your system with unnecessary global files.

Global Mode

• The global mode is used to install packages you want Node.js to use globally.
• Usually these are CLI tools, such as Gulp.
• Most of the time, the package author will specifically instruct you to install the package globally. Therefore, whenever in doubt, use the local mode.
• The global mode will usually install the packages in the C:\Users\%USERNAME%\AppData\Roaming\npm\ node_modules folder for Windows-based systems, making it available to any Node.js application running on the system.

How to Install a package using NPM ?

Step 1 :

• Once you find the right package, you'll be able to install it using the npm install command as follows.

Local Mode :

• Run 'Command Prompt' with “Administrative Privileges”.
• Go to your Node.js App's root folder.

          npm install <Package Unique Name>

      e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm install express

• The preceding command will install the latest stable version of the Express package in your local node_modules folder as follows. 

• When a package has dependencies, NPM will automatically resolve those dependencies, installing the required packages in a node_modules folder inside the package folder as follows.

Global Mode :

• Run 'Command Prompt' with “Administrative Privileges”.
• Installing a module globally is similar to its local counterpart, but you'll have to add the –g flag as follows.

          npm install –g <Package Unique Name>

      e.g. 
            D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm install -g express

• The preceding command will install the latest stable version of the Express package in your Roaming folder as follows. 
• Note that the "AppData" folder is Hidden by default. 

How to Remove a package using NPM ?

• To remove an installed package, you have to navigate to your application folder and run the following command according to the mode.

Local Mode :

         npm uninstall < Package Unique Name>

  e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm uninstall express

Global Mode :
        npm uninstall –g < Package Unique Name>

  e.g.        
          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm uninstall –g express

How to Update a package using NPM ?

• To update a package to its latest version, issue the following command according to the mode.

Local Mode :

         npm update < Package Unique Name>

  e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm update express

Global Mode :
        npm update –g < Package Unique Name>

  e.g.        
          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm update –g express

What is a package.json file ?

• The package.json file is basically a JSON file that contains the different attributes you'll need to describe about your application properties.
• Your application will need to use several packages, and so you'll need a better way to manage these package dependencies.
• For this purpose, NPM allows you to use a configuration file named package.json in the root folder of your application.
• In your package.json file, you can define various metadata properties of your application, including properties such as the name, version, and author of your application. 
• This is also where you define your application dependencies.
• Let's say our application is using the Express and Gulp packages.So then we will have a package.json file as follows.

                           {
                               "name" : "MEAN App",
                               "version" : "0.0.1",
                               "author" : "Sampath Lokuge", 
                               "dependencies" : {

                                     "express" : "latest",

                                     "gulp" : "latest"

                                    }

                           }

            

Important Note :

• Your application name and version properties are required.
• If you remove these properties then NPM will not work properly.
• The "latest" keyword to tell NPM to install the latest versions of the packages. 

How to Create a package.json file ?

• Go to your Node.js App's root folder.

          npm init

e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm init

• NPM will ask you a few questions about your application and will automatically create a new package.json file for you.
• A sample screenshot as follows.

How to Install the package.json dependencies ?

install :

• If you need to install Gulp,then change the package.json file's dependencies section as follows.

           "dependencies": {

                    "express": "^4.11.2",

                    "gulp": "latest"

            }

• In the preceding code example, I have used the "latest" keyword to tell NPM to install the latest versions of the Gulp package. 
• Navigate to your application's root folder and use the "npm install" command as follows.

          npm install

  e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>npm install

• NPM will automatically detect your package.json file and will install all your application dependencies.
• You can find out them under a local "node_modules" folder. 

update :

• An alternative and sometimes better approach to install your dependencies is to use the "npm update" command.
• This will install any missing packages and will update all of your existing dependencies to their specified version.

          npm update

e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test> npm update

How to Update the package.json file ?

• Another great feature of the npm install command is the ability to install a new package and save the package information as a dependency in your package.json file.
• This can be accomplished using the --save optional flag when installing a specific package.
• For example, to install the latest version of Express and save it as a dependency, you can issue the following command.

         npm install express --save

e.g.        

          D:\Freelance Work\My Blog\Mean Introduction\NodeJs\Test>  npm install express --save

• In the preceding command will install the latest version of Express and will add the express package as a dependency to your package.json file. 

                        {

                             "name": "MEAN",

                             "version": "0.0.1",

                                   "dependencies": {

                                            "express": "^4.11.2",

                                       },

                        }

References

• Node.Js Home
• npm Home

Related Post

• MEAN Stack Development with MongoDB

Conclusion

• In this article, You learned how to install Node.js and usage of the Node.js CLI.
• You learned about NPM and discovered how to use it to download and install Node.js packages.
• You also learned how to easily manage your application dependencies using the package.json file.
• In the next article,we'll discuss the basics of Express.js.
• I hope this helps to You.Comments and feedback greatly appreciated.

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