An Introduction of Node Package Manger (NPM)

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iFour Consultancy
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Introduction

• NPM is a package manager for the JavaScript
  programming language. It is the default package
  manager for the JavaScript runtime environment
  Node.js. It consists of a command line client,
  also called npm, and an online database of public
  and paid-for private packages, called the npm
  registry. The registry is accessed via the
  client, and the available packages can be browsed
  and searched via the npm website. The package
  manager and the registry are managed by npm, Inc.
• NPM is included as a recommended feature in
  Node.js installer.npm consists of a command line
  client that interacts with a remote registry. It
  allows users to consume and distribute JavaScript
  modules that are available on the registry.

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What is NPM?

• NPM is the world's largest Software Library
  (Registry).
• NPM is also a software Package Manager and
  Installer.
• The registry contains over 800,000 code packages.
• Open-source developers use npm to share software.
• Many organizations also use npm to manage private
  development.

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Node Package Manager

• npm is a package manager for Node.js with
  hundreds of thousands of packages. Although it
  does create some of your directory
  structure/organization, this is not the main
  purpose.
• The main goal, as you touched upon, is automated
  dependency and package management. This means
  that you can specify all of your project's
  dependencies inside your package.json file, then
  any time you (or anyone else) needs to get
  started with your project they can just run npm
  install and immediately have all of the
  dependencies installed. On top of this, it is
  also possible to specify what versions your
  project depends upon to prevent updates from
  breaking your project.

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Node Package Manager

• It is definitely possible to manually download
  your libraries, copy them into the correct
  directories, and use them that way. However, as
  your project (and list of dependencies) grows,
  this will quickly become time-consuming and
  messy. It also makes collaborating and sharing
  your project that much more difficult.
• Hopefully this makes it more clear what the
  purpose of npm is. As a Javascript developer
  (both client-side and server-side), npm is an
  indispensable tool in my workflow.
• npm is free to use.
• You can download all npm public software packages
  without any registration or logon.

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Installing NPM

• npm includes a CLI (Command Line Client) that can
  be used to download and install software

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Software Package Manager

• The name npm (Node Package Manager) stems from
  when npm first was created as a package manager
  for Node.js.
• npm is installed with Node.js
• All npm packages are defined in files called
  package.json.
• The content of package.json must be written in
  JSON.
• At least two fields must be present in the
  definition file name and version.

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Package.Json

• How to generate package.json file.
• Here is Package.Json file

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Attributes of Package.json

• name - name of the package
• version - version of the package
• description - description of the package
• homepage - homepage of the package
• author - author of the package
• contributors - name of the contributors to the
  package
• dependencies - list of dependencies. NPM
  automatically installs all the dependencies
  mentioned here in the node_module folder of the
  package.
• repository - repository type and URL of the
  package
• main - entry point of the package
• keywords - keywords

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Installing Packages

• There is a simple syntax to install any Node.js
  module -
• syntex
• npm install ltModule Namegt
• For example, following is the command to install
  a famous Node.js web framework module called
  express
• npm install express
• We have two ways to install package.
• Install package local
• Install package global

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Install package local

• By default, NPM installs any dependency in the
  local mode. Here local mode refers to the package
  installation in node_modules directory lying in
  the folder where Node application is present.
  Locally deployed packages are accessible via
  require() method. For example, when we installed
  express module, it created node_modules directory
  in the current directory where it installed the
  express module.
• local packages are installed in the directory
  where you run npm install ltpackage-namegt, and
  they are put in the node_modules folder under
  this directory.
• For example
• npm install express

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Install package global

• Globally installed packages/dependencies are
  stored in system directory. Such dependencies can
  be used in CLI (Command Line Interface) function
  of any node.js but cannot be imported using
  require() in Node application directly. Now let's
  try installing the express module using global
  installation.
• For example
• npm install express -g

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Adding dependency

• Adding dependency in package.json
• For example

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Adding dependency

• Here is Package.Json file
• express dependency (package) we add into
  package.json file

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Updating packages

• Update Package
• Update package.json and change the version of the
  dependency to be updated and run the following
  command.
• For example
• npm update express
• Search a package
• Search a package name using NPM.
• For example
• npm search express

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Installing Nodemon

• Nodemon is a utility that will monitor for any
  changes in your source and automatically restart
  your server. Perfect for Nodejs development.
  Install it using npm.
• Just use nodemon instead of node to run your
  code, and now your process will automatically
  restart when your code changes. To install, get
  node.js, then from your terminal run
• npm install -g nodemon

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Features of Nodemon

• Automatic restarting of application.
• Detects default file extension to monitor.
• Default support for node coffeescript, but easy
  to run any executable (such as python, make,
  etc).
• Ignoring specific files or directories.
• Watch specific directories.
• Works with server applications or one time run
  utilities and REPLs.
• Requirable in node apps.
• Open source and available on github.

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