|This article relies too much on references to primary sources. (September 2015) (Learn how and when to remove this template message)|
|Original author(s)||Ryan Dahl|
|Developer(s)||Node.js Developers, Joyent, contributors|
|Initial release||May 27, 2009|
|Development status||Active (complete release list)|
|Operating system||macOS, Linux, Solaris, FreeBSD, OpenBSD, Microsoft Windows (older versions require Cygwin), webOS, NonStop OS|
Node.js has an event-driven architecture capable of asynchronous I/O. These design choices aim to optimize throughput and scalability in Web applications with many input/output operations, as well as for real-time Web applications (e.g., real-time communication programs and browser games).
Corporate users of Node.js software include GoDaddy, Groupon, IBM, LinkedIn, Microsoft, Netflix, PayPal, Rakuten, SAP, Voxer, Walmart, Yahoo!, and Cisco Systems.
Dahl was inspired to create Node.js after seeing a file upload progress bar on Flickr. The browser did not know how much of the file had been uploaded and had to query the Web server. Dahl desired an easier way.
Dahl criticized the limited possibilities of the most popular web server in 2009, Apache HTTP Server, to handle a lot of concurrent connections (up to 10,000 and more) and the most common way of creating code (sequential programming), when code either blocked the entire process or implied multiple execution stacks in the case of simultaneous connections. 
In January 2010, a package manager was introduced for the Node.js environment called npm. The package manager makes it easier for programmers to publish and share source code of Node.js libraries and is designed to simplify installation, updating and uninstallation of libraries.
In January 2012, Dahl stepped aside, promoting coworker and npm creator Isaac Schlueter to manage the project. In January 2014, Schlueter announced that Timothy J. Fontaine would lead the project.
In February 2015, the intent to form a neutral Node.js Foundation was announced. By June 2015, the Node.js and io.js communities voted to work together under the Node.js Foundation.
In September 2015, Node.js v0.12 and io.js v3.3 were merged back together into Node v4.0. This brought V8 ES6 features into Node.js, and a long-term support release cycle. As of 2016, the io.js website recommends that developers switch back to Node.js and that no further releases are planned due to the merger.
Node.js is primarily used to build network programs such as Web servers. The biggest difference between Node.js and PHP is that most functions in PHP block until completion (commands execute only after previous commands have completed), while functions in Node.js are designed to be non-blocking (commands execute in parallel, and use callbacks to signal completion or failure).
Programmers have built thousands of open-source libraries for Node.js - most of them hosted on the npm website. The Node.js developer community has two main mailing lists and the IRC channel #node.js on freenode. There is an annual Node.js developer conference, called NodeConf.
The open-source community has developed server frameworks to accelerate the development of applications. Such frameworks include Connect, Express.js, Socket.IO, Koa.js, Hapi.js, Sails.js, Meteor, Derby, and many others.
Modern desktop IDEs provide editing and debugging features specifically for Node.js applications. Such IDEs include Atom, Brackets, JetBrains WebStorm, Microsoft Visual Studio (with Node.js Tools for Visual Studio, or TypeScript with Node definitions), NetBeans, Nodeclipse Enide Studio (Eclipse-based) and Visual Studio Code. Certain online web-based IDEs also support Node.js, such as Codeanywhere, Codenvy, Cloud9 IDE and Koding.
||This section may be too technical for most readers to understand. (August 2015) (Learn how and when to remove this template message)|
Node.js operates on a single thread, using non-blocking I/O calls, allowing it to support tens of thousands of concurrent connections without incurring the cost of thread context switching. The design of sharing a single thread between all the requests that uses the observer pattern is intended for building highly concurrent applications, where any function performing I/O must use a callback. In order to accommodate the single-threaded event loop, Node.js utilizes the libuv library that in turn uses a fixed-sized threadpool that is responsible for some of the non-blocking asynchronous I/O operations.
A downside of this single-threaded approach is that Node.js doesn't allow vertical scaling by increasing the number of CPU cores of the machine it is running on without using an additional module, such as cluster, StrongLoop Process Manager or pm2. However, developers can increase the default number of threads in the libuv threadpool; these threads are likely to be distributed across multiple cores by the server operating system.
Execution of parallel tasks in Node.js is handled by a thread pool. The main thread call functions post tasks to the shared task queue that threads in the thread pool pull and execute. Inherently non-blocking system functions like networking translates to kernel-side non-blocking sockets, while inherently blocking system functions like file I/O run in a blocking way on its own thread. When a thread in the thread pool completes a task, it informs the main thread of this that in turn wakes up and execute the registered callback. Since callbacks are handled in serial on the main thread, long lasting computations and other CPU-bound tasks will freeze the entire event-loop until completion.
Node.js uses libuv to handle asynchronous events. Libuv is an abstraction layer for network and file system functionality on both Windows and POSIX-based systems like Linux, macOS, OSS on NonStop and Unix.
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, organizing the installation and management of third-party Node.js programs. npm is not to be confused with the CommonJS require() statement. It is not used to load code; instead, it is used to install code and manage code dependencies from the command line. The packages found in the npm registry can range from simple helper libraries like Underscore.js to task runners like Grunt.
Node.js registers itself with the operating system so that it is notified when a connection is made, and the operating system will issue a callback. Within the Node.js runtime, each connection is a small heap allocation. Traditionally, relatively heavyweight OS processes or threads handled each connection. Node.js uses an event loop for scalability, instead of processes or threads. In contrast to other event-driven servers, Node.js's event loop does not need to be called explicitly. Instead callbacks are defined, and the server automatically enters the event loop at the end of the callback definition. Node.js exits the event loop when there are no further callbacks to be performed.
Similar open source event-driven server frameworks for other platforms include:
- EventMachine for Ruby
- libevent for C
- Perl Object Environment for Perl
- Twisted for Python
Node.js may utilize code written in other programming languages using:
- Edge.js allows Microsoft .NET applications to run Node.js scripts in-process, and allows Node.js servers to utilize .NET compiled code via async callbacks.
- Luvit implements the Node.js APIs for the language Lua
- Node-julia allows using Julia with Node.js/io.js
- The COBOL bridge for Node.js allows using COBOL with Node.js
- "node-v0.x-archive on GitHub". Retrieved 2 August 2014.
- "Node.js Changelog". Retrieved 2017-01-04.
- "Node.js Changelog". Retrieved 2017-01-05.
- Wen, Ben (2013-12-12). "6 things you should know about Node.js". JAVAWORLD. Archived from the original on 2013-12-12. Retrieved 2016-01-22.
- Laurent Orsini (2013-11-07). "What You Need To Know About Node.js". readwrite. Archived from the original on 2013-11-07. Retrieved 2016-01-22.
- "Node.js Foundation - Node.js". Retrieved 4 July 2015.
- "Linux Foundation Collaborative Projects". Retrieved 4 July 2015.
- Why GoDaddy's Nodejitsu deal is great for Node.js, VentureBeat, February 10, 2015
- Geitgey, Adam (30 October 2013). "I-Tier: Dismantling the Monoliths". Groupon. Retrieved 30 April 2014.
- "IBM Bluemix". Retrieved 4 July 2015.
- "You'll never believe how LinkedIn built its new iPad app". VentureBeat. May 2, 2012. Retrieved May 10, 2012.
- "Blazing fast node.js: 10 performance tips from LinkedIn Mobile". Retrieved 7 April 2015.
- Baxter-Reynolds, Matthew (November 9, 2011). "Here's why you should be happy that Microsoft is embracing Node.js". London: The Guardian. Retrieved May 10, 2012.
- "WebMatrix - Front End Web Developers take note (ASP.NET, PHP, node.js and more)". Retrieved 2 August 2014.
- Node.js in Flames November 19, 2014
- "Clash of the Titans: Releasing the Kraken, NodeJS @paypal". fluentconf.com. May 28, 2013. Retrieved September 11, 2013.
- "All such companies and their products in which Node.js is used". Retrieved 2 August 2014.
- "SAP AppBuilder". SAP. March 10, 2014. Retrieved March 10, 2014.
- "Why Walmart is using Node.js". VentureBeat. January 24, 2012. Retrieved May 10, 2012.
- "Yahoo! Announces Cocktails Shaken, Not Stirred". Retrieved 7 April 2015.[dead link]
- "About Node.js, and why you should add Node.js to your skill set?". Training.com. Training.com. Retrieved 23 October 2016.
- Ryan Dahl (2010-11-09). "Joyent and Node". Google Groups. Retrieved 2015-02-05.
- Harris, Amber (April 1, 2012). "The Birth of Node: Where Did it Come From? Creator Ryan Dahl Shares the History". Devops Angle. Retrieved 26 October 2013.
- "PHP 7 vs Node.js? They Can Be Partners, Not Competitors For a Developer!". Retrieved 21 December 2016.
- Sams Teach Yourself Node.js in 24 Hours, Sams Publishing, 05-Sep-2012
- "Ryan Dahl at JSConf EU 2009".
- "Ryan Dahl at JSConf EU 2009 Video".
- "Video: Node.js by Ryan Dahl".
- "Earliest releases of npm". GitHub. Retrieved 27 July 2016.
- "Porting Node to Windows With Microsoft's Help". Retrieved 17 April 2016.
- Dahl, Ryan. "New gatekeeper". Retrieved 26 October 2013.
- Schlueter, Isaac (January 15, 2014). "The Next Phase of Node.js". Retrieved 21 January 2014.
- Krill, Paul (Dec 4, 2014). "Why io.js Decided to Fork Node.js". JavaWorld. Retrieved Dec 15, 2014.
- Q&A: Why io.js decided to fork Node.js, Infoworld Tech Watch
- Mikeal, Rogers (January 28, 2015). "State of io.js". Retrieved 2 February 2015.
- "Node.js Foundation Advances Community Collaboration, Announces New Members and Ratified Technical Governance". Retrieved 4 July 2015.
- "Node.js Foundation Combines Node.js and io.js Into Single Codebase in New Release". Retrieved 28 Jan 2016.
- "io.js and Node.js merge". Retrieved 27 June 2015.
- Node.js for PHP Developers, O'Reilly Media, Inc., 2013
- Node.js Essentials, Packt Publishing, 09-Sep-2014
- Sahil Chitkara. "Streams in node.js : Readable and Writable". TO THE NEW BLOG.
- Modules, Nodejs Website
- "bomBora - Node.js for NonStop". Infrasoft. Retrieved 14 August 2015.
- "CoffeeScript on Node.js". O'Reilly Media, Inc. April 15, 2013. Retrieved May 17, 2015.
- Finley, Klint (April 7, 2011). "NodeConf Schedule Announced". ReadWriteHack. Retrieved 2 August 2014.
- Express.js Guide: The Comprehensive Book on Express.js, Azat Mardan, 28-May-2014
- Node.js, WebStorm supports integration with the Node.js runtime environment, WebStorm Help
- Running and Debugging Node.js, WebStorm Help
- "Node.js Tools for Visual Studio". Retrieved 1 Feb 2016.
- soywiz/typescript-node-definitions TypeScript's typings for some popular node.js modules, GitHub
- DefinitelyTyped, GitHub
- The repository for high quality TypeScript type definitions Archived February 3, 2016, at the Wayback Machine.
- ImageBoard, A Node.js + Express + MongoDB application built using TypeScript on the server, TypeScript Samples
- Krill, Paul (2015-11-10). "Node.js takes center stage in NetBeans 8.1". InfoWorld.
- Nodeclipse, Enide -- Node.JS development in Eclipse, Nodeclipse Website
- Hello Visual Studio Code (with NodeJS), Channel 9, Microsoft
- Node.js Applications with VS Code, Visual Studio Code
- "Node.js w/1M concurrent connections!". caustik's blog.
- "Cluster Node.js v5.5.0 Manual & Documentation".
- "StrongLoop Process Manager".
- "GitHub - Unitech/pm2: Production process manager for Node.js applications with a built-in load balancer". GitHub.
- Aleksander Kasiuk (22 April 2015). "On problems with threads in node.js - Future Processing".
- "PostgreSQL: Documentation: 9.4: JSON Types". www.postgresql.org. Retrieved 2016-10-20.
- About Node.js, Node.js Website
- Serdar Yegulalp (20 February 2015). "Node.js fork JXcore goes open source, aims for mobile developers". InfoWorld. Retrieved 4 July 2015.
- "jxcore/jxcore". GitHub.
- "Nubisa halting active development on JXcore platform".
- Tomasz Janczuk. "Edge.js".
- Using Edge.js to combine Node.js and .NET, .NET Curry
- Edge.js bridges the gap between Node.js and .NET, TechRepublic, Tony Patton, July 1, 2014
- 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 978-1-118-22754-1
- Randal L. Schwartz and Aaron Newcomb (9 January 2013). "Episode 237: Node.js". twit.tv/show/floss-weekly (Podcast). TWiT.tv. Event occurs at 1:08:13. Retrieved 9 January 2013.
- Kurniawan, Agus (July 2012), Nodejs Programming By Example (First ed.), PE Press, p. 67
- Gackenheimer, Cory (October 2013), Node.js Recipes: A Problem-Solution Approach (First ed.), Apress, p. 376, ISBN 978-1-4302-6058-5
- Ribeiro Pereira, Caio (February 2016), Building APIs with Node.js (First ed.), Leanpub, p. 152
|Wikimedia Commons has media related to Node.js.|