As described in Chapter 2, Setting up Node.js, npm is a package management and distribution system for Node.js. It has become the de-facto standard for distributing modules (packages) for use with Node.js. Conceptually, it's similar to tools such as
MacPorts (Mac OS X),
CPAN (Perl), or
PEAR (PHP). Its' purpose is publishing and distributing Node.js packages over the Internet using a simple command-line interface. With npm, you can quickly find packages to serve specific purposes, download them, install them, and manage packages you've already installed.
npm package defines a package format for Node.js largely based on the CommonJS package specification. It ...