Node.js

Node.js

Original author(s)	Ryan Lienhart Dahl
Developer(s)	Node.js Developers, Joyent
Stable release	0.8.18 / January 18, 2013 (2013-01-18)
Preview release	0.9.8 / January 24, 2013 (2013-01-24)
Development status	Active
Written in	C++, JavaScript
Operating system	Mac OS X, Linux, Solaris, FreeBSD, OpenBSD, Windows (older versions require Cygwin), webOS
Type	Event-driven networking
License	MIT License
Website	nodejs.org

Node.js is a server side software system designed for writing scalable Internet applications, notably web servers. Programs are written on the server side in JavaScript, using event-driven, asynchronous I/O to minimize overhead and maximize scalability.

Details

Node.js is a packaged compilation of Google's V8 JavaScript engine, the libUV platform abstraction layer, and a core library, which is itself primarily written in JavaScript.

Node.js was created by Ryan Dahl starting in 2009, and its growth is sponsored by Joyent, his former employer.

Dahl's original goal was to create web sites with push capabilities as seen in web applications like Gmail. After trying solutions in several other programming languages he chose JavaScript because of the lack of an existing I/O API. This allowed him to define a convention of non-blocking, event-driven I/O.

Similar environments written in other programming languages include Twisted for Python, Perl Object Environment for Perl, libevent for C, Vert.x for Java and EventMachine for Ruby. Unlike most JavaScript programs, it is not executed in a web browser, but instead as a server-side JavaScript application. Node.js implements some CommonJS specifications. It provides a REPL environment for interactive testing.

Examples

This is a complete implementation of hello world as an HTTP Server in Node.js:

var http = require('http');
 
http.createServer(
  function (request, response)
  {
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.end('Hello World\n');
  }
).listen(8000);
 
console.log('Server running at http://localhost:8000/');

The following code is a simple TCP server which listens on port 7000 and echoes 'hello' upon connection:

var net = require('net');
 
net.createServer(
  function (stream)
  {
    stream.write('hello\r\n');
 
    stream.on( 'end',
      function ()
      {
        stream.end('goodbye\r\n');
      }
    );
 
    stream.pipe(stream);
  }
).listen(7000);

Community

Node.js has a developer community primarily centered around two mailing lists, nodejs and nodejs-dev, and the IRC channel #node.js on freenode. The community gathers at NodeConf, an annual developer conference focused on Node.js.

Node.js is currently used by a number of large companies including LinkedIn, Microsoft, Yahoo! and Walmart.

See also

• npm – the predominant package manager for Node.js. As of Node.js version 0.6.3, npm is installed automatically with Node.js

Further reading

• Hughes-Croucher, Tom; Wilson, Mike (April, 2012), Up and Running with Node.js (First ed.), O'Reilly Media, p. 204, ISBN 978-1-4493-9858-3
• Ornbo, George (September, 2012), Sams Teach Yourself Node.js in 24 Hours (First ed.), SAMS Publishing, p. 440, ISBN 978-0-672-33595-2
• Teixeira, Pedro (October, 2012), Professional Node.js (First ed.), John Wiley & Sons, p. 408, ISBN 978-1-1182-2754-1, http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1118185463,descCd-authorInfo.html
• Randal L. Schwartz and Aaron Newcomb (9 January 2013). "Episode 237: Node.js". http://twit.tv/show/floss-weekly (Podcast). TWiT.tv. Event occurs at 1:08:13. http://twit.tv/show/floss-weekly/237. Retrieved 9 January 2013.

External links

• Official website
• npm