Node.js Package Manager

Node Package Manager provides two main functionalities:

• It provides online repositories for node.js packages/modules which are searchable on search.nodejs.org
• It also provides command line utility to install Node.js packages, do version management and dependency management of Node.js packages.

The npm comes bundled with Node.js installables in versions after that v0.6.3. You can check the version by opening Node.js command prompt and typing the following command:

1. npm  version  

Installing Modules using npm

Following is the syntax to install any Node.js module:

1. npm install <Module Name>  

Let's install a famous Node.js web framework called express:

Open the Node.js command prompt and execute the following command:

1. npm install express  

You can see the result after installing the "express" framework.

Global vs Local Installation

By default, npm installs dependency in local mode. Here local mode specifies the folder where Node application is present. For example if you installed express module, it created node_modules directory in the current directory where it installed express module.

You can use npm ls command to list down all the locally installed modules.

Open the Node.js command prompt and execute "npm ls":

Globally installed packages/dependencies are stored in system directory. Let's install express module using global installation. Although it will also produce the same result but modules will be installed globally.

Open Node.js command prompt and execute the following code:

1. npm install express -g  

Here first line tells about the module version and its location where it is getting installed.

Uninstalling a Module

To uninstall a Node.js module, use the following command:

1. npm uninstall express  

The Node.js module is uninstalled. You can verify by using the following command:

1. npm ls  

You can see that the module is empty now.

Searching a Module

"npm search express" command is used to search express or module.

1. npm search express