20 May 2015

Introduction Node.js

What is Node.js?

Ryan Dahl, and other developers, at Joyent created Node.js.  Node.js is an open source, cross-platform runtime environment for server-side and networking applications. It brings event-driven programming to web servers enabling development of fast web servers in Javascript.

In an event-driven application, there is a main loop that listens for events, and then triggers a callback function when one of those events is detected. Node.js also provides a non-blocking I/O API that optimizes an application's throughput and scalability.   In a non-blocking language, commands execute in parallel, and use callbacks to signal completion.  In a blocking language, commands execute only after the previous command has completed.Node.js uses the Google V8 JavaScript engine to execute code, and a large percentage of the basic modules are written in JavaScript.

Node.js contains a built-in library to allow applications to act as a Web server without software such as Apache HTTP Server or IIS.NPM is the pre-installed package manager for the Node.js server platform. It is used to install Node.js programs from the npm registry.  The package manager allows publishing and sharing of open-source Node.js libraries by the community, and simplifies installation, updating and un-installation of libraries.